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CuriosityCh 4 Magnets ki Khoj

Exploring Magnets (Magnets ki Khoj): Class 6 Science Chapter 4 Hinglish mein

Curiosity · Hinglish notes, simulations aur practice · Official NCERT chapter PDF ↗

Published · Updated

  • 75 min
  • 3 simulations
  • 15 practice questions
  • 20 MCQs

Is chapter mein aap kya seekhenge

  • Roz ki cheezon ko magnet se test karna aur unhe magnetic aur non-magnetic materials mein sort karna
  • Magnet ke poles dhoondhna aur samjhana ki har magnet mein north aur south, dono poles kyun hote hain
  • Freely latakte magnet ya magnetic compass se north, south, east aur west pata karna
  • Steel ki needle ko magnetise karke ek kaam karne wala compass banana
  • Predict karna ki do poles attract karenge ya repel, aur repulsion se magnet aur plain iron mein farq pehchanna
  • Dikhana ki magnet wood, cardboard, plastic aur glass ke aar-paar bhi kaam karta hai
  • Magnets ko aise sambhalna aur rakhna ki woh strong bane rahein

NCERT Science Class 6, Chapter 4, pp. 61–78 par based original companion text. Yeh NCERT se juda nahi hai aur NCERT ne ise endorse nahi kiya hai.

Hamare aas-paas magnets

Click! School bag ka flap apne aap band ho jaata hai. Hilti-dulti train mein bhi travel ludo ke counters board par tike rehte hain. Ek bookmark page par jam jaata hai aur kabhi nahi phisalta. Yeh sab chupchaap kaun kar raha hai? In sab cheezon ke andar ek magnet chhupa hai. Magnet ko Hindi mein चुंबक kehte hain. Radio ke speaker mein bhi ek magnet hota hai!

2/2Chhupe hue magnets dikh gaye: ludo counter ke neeche, bookmark ke andar, bag flap ke neeche aur speaker cone ke peeche.

Fig. 4.1Roz use hone wali kai cheezon mein ek chhota magnet chhupa hota hai.NCERT Fig. 4.1 · p. 62

Chaar cheezein ek line mein khadi hain, neeche unke labels hain: gol counters wala travel ludo board, ek kitaab jiske upar ke edge par bookmark laga hai, flap wala school bag, aur do gol cones wala chhota box speaker. Pehle step mein ek heading poochti hai ki magnets kahan hain. Doosre step mein cheezein halki pad jaati hain aur har ek ke andar ek chhota laal-neela magnet dikhta hai, jiske chaaron taraf dashed ring hai: ludo counter ke neeche, bookmark ke andar, bag flap ke neeche aur bade speaker cone ke peeche.

Sabse pehle magnets kahan se aaye? Unhe kisi ne banaya nahi tha. Woh kaale patthar the jo iron ke tukdon ko apni taraf kheenchte the. In natural magnets ko hum lodestones kehte hain. Phir logon ne ek trick dhoondhi: iron ke tukde ko lodestone se stroke karo (ragdo), to iron bhi magnet ban jaata hai. Aisi hi ek trick tum Activity 4.4 mein try karoge. Aajkal lagbhag har magnet factory mein banta hai, iron, steel ya metals ke khaas mixtures se.

Magnets kai shapes mein aate hain. Lamba, chapta bar magnet lab ka favourite hai. Iske alawa U-shaped magnets, beech mein ched wale chapte ring magnets, discs, cylinders aur balls bhi hote hain. Inmein se kuch tum Fig. 4.5 mein dekhoge.

4.1 Magnetic aur Non-magnetic Materials

Kya magnet chaabi utha lega? Sikka? Sone ki baali? Bahut log sochte hain ki magnet har metal ko pakad leta hai. Scientists sirf guess nahi karte. Woh pehle predict karte hain, phir test karte hain, phir jo sach mein hua use record karte hain. Chalo, hum bhi aise hi kaam karein.

Apni table phir se dekho. Jo bhi cheez magnet ki taraf uchhli, usmein iron tha. To iron ek magnetic material hai: aisa material jise magnet attract karta hai. Sirf kuch hi aur metals iron jaise behave karte hain. Yaad rakhne wale do metals hain nickel aur cobalt. In metals se bane kai mixtures bhi chipakte hain. Inmein sabse zyada dikhne wala mixture steel hai. Usmein zyadatar iron hota hai aur thoda sa carbon, isliye steel ki zyadatar cheezein chipakti hain.

Ab un cheezon ko dekho jo apni jagah par hi rahi. Wood, plastic, rubber, glass, paper aur cloth kabhi magnet ki taraf nahi jaate. Yeh non-magnetic materials hain. Sabse bada surprise yeh hai ki kai metals bhi isi group mein aate hain. Aluminium, copper, brass, silver aur gold, sab magnet ko ignore karte hain.

Definition
Magnetic material

Aisa material jise magnet attract karta hai, jaise iron, nickel, cobalt ya zyadatar tarah ke steel.

ExampleIron nail, steel ka paper clip, crown bottle cap.

Definition
Non-magnetic material

Aisa material jise magnet attract nahi karta.

ExampleWood, plastic, glass, rubber, aluminium, copper, brass aur gold.

3/3Sort ho gaya! Nail, clip aur bottle cap magnetic hain. Eraser, brass ki chaabi aur marble non-magnetic hain.

Fig. 4.2Predict karo, test karo, phir sort karo: sirf kuch cheezein magnetic hain.NCERT Fig. 4.3 · p. 63

Ek lamba laal-neela bar magnet table par rakhi chhe labelled cheezon ki line ke upar latka hai, har cheez par question mark hai: iron nail, eraser, paper clip, brass ki chaabi, bottle cap aur glass marble. Doosre step mein magnet neeche aata hai aur nail, clip aur bottle cap uchhal kar usse chipak jaate hain, jabki eraser, chaabi aur marble table par hi rehte hain. Teesre step mein magnet wapas upar hai aur cheezein do dashed boxes mein sort ho gayi hain: left mein magnetic, jismein nail, clip aur cap hain, aur right mein non-magnetic, jismein eraser, chaabi aur marble hain.

SimulationMagnet test lab

Ek bar magnet jise tum drag kar sakte ho aur ghuma sakte ho, roz ki cheezon ki do lines ke upar: iron nail, glass, aluminium foil, wood, steel ka chammach, paper clip, rubber, copper wire, plastic aur nickel ka sikka. Magnetic cheezein uchhal kar magnet se chipak jaati hain; baaki jahan hain wahin rehti hain. Ek switch se magnet ke aas-paas iron filings dikhti hain.

Fig. 4.3Magnet ko cheezon ke upar drag karo, ya har cheez ko drag karke magnet tak le jaao.
Try karo
  • Magnet ko dheere-dheere poori line ke upar se le jaao. Kaun si cheezein chipakti hain? Kya kisi ne tumhe surprise kiya?
  • Copper wire aur aluminium foil dono metals hain. Kya woh chipakte hain?
  • Iron filings switch on karo. Filings kahan jama hoti hain?
Quick check
3 mein se 1
Magnet inmein se kise kheenchega? Jitne sahi hain, sab chuno.
Saare sahi options chuno
Answer dekho
Answer
  • (A) iron ka key ring
  • (C) steel ki safety pin
  • (E) nickel ki patti
Iron, steel (zyadatar iron) aur nickel magnetic hain. Copper aur gold bhi metals hain, lekin woh magnetic nahi hain, isliye magnet unhe ignore karta hai.

4.2 Magnet ke Poles

Kya magnet ka har hissa ek jaisa kheenchta hai? Yeh pata karne ka ek badhiya tareeka hai. Tumhe iron ke bahut chhote tukde chahiye, jinhe iron filings kehte hain. Har tukda itna halka hota hai ki kamzor pull bhi use hila deta hai.

3/3Zyadatar filings dono ends par, yaani poles par, jama hoti hain. Beech mein bas thodi si hoti hain.

Fig. 4.4Iron filings dikhati hain ki magnet kahan sabse zyada kheenchta hai.NCERT Fig. 4.4 · p. 64

Halke rang ka ek paper, jis par iron filings chhote kaale dashes ki tarah bani hain. Pehle step mein filings poore paper par barabar bikhri hain, ek label par iron filings likha hai, aur ek laal-neela bar magnet upar pakda hua hai. Doosre step mein magnet paper ke beech mein rakha hai aur zyadatar filings uske dono ends par pahunch gayi hain, jahan woh kaanton jaise gucchhon mein khadi hain. Teesre step mein dashed circles dono gucchhon ko highlight karte hain, har ek par pole likha hai, aur ek arrow magnet ke centre ki taraf hai, jahan bas thodi si filings hain.

Ends ke paas ki yeh strong jagahein magnet ke poles hain (Hindi mein ध्रुव). Magnet ke hamesha do poles hote hain. Ek uska north pole (N) hota hai aur doosra uska south pole (S). North aur south hi kyun? Section 4.3 mein pata chalega.

Definition
Magnet ka pole

Magnet ki woh jagah jahan uska pull sabse strong hota hai. Har magnet ke do poles hote hain, north (N) aur south (S).

ExampleBar magnet ke dono ends; U-shaped magnet ki dono tips.

Doosri shapes ke magnets ke bhi poles hote hain, lekin hamesha wahan nahi jahan tum sochoge. U-shaped magnet mein poles dono tips par hote hain. Ring magnet ya disc mein dono chapte faces hi poles hote hain. Fig. 4.5 dikhata hai ki filings har shape ke poles kaise dhoondh leti hain.

3/3Har magnet ka ek north (N) aur ek south (S) pole hai, theek wahan jahan uski filings jama hui thi.

Fig. 4.5Shape kuch bhi ho, har magnet ka ek north aur ek south pole hota hai.NCERT More to know! · p. 78

Chaar grey magnets ek line mein khade hain, neeche labels hain: U-shaped, ring, cylinder aur ball. Doosre step mein iron filings ke gucchhe dikhte hain: U ki dono tips par, jinke beech ke gap mein bhi kuch filings pul jaisa banati hain; ring ke upar wale face ke upar aur neeche wale face ke neeche; cylinder ke upar aur neeche ke ends par; aur ball ki left aur right sides par. Teesre step mein pole wali jagahein N ke liye laal aur S ke liye neeli ho jaati hain aur un par letters likhe hote hain, jabki filings halki pad jaati hain.

Kya magnet ka sirf ek pole ho sakta hai?

Maan lo tum bar magnet ko beech se tod dete ho. Kya ek aadha sirf north wala magnet hoga, aur doosra sirf south wala? Nahi! Har aadha turant ek poora magnet ban jaata hai, jiska apna N aur S hota hai. Tukdon ko phir todo, to phir wahi hota hai. Tukda kitna bhi chhota ho, poles hamesha jodi mein aate hain.

3/3Chaar chhote magnets, har ek ka apna N aur S: kul 8 poles.

Fig. 4.6Magnet todo to aur magnets milte hain, kabhi akela pole nahi.

Ek lamba bar magnet, left mein N ke liye laal aur right mein S ke liye neela, upar ek heading jo tukde aur poles ginti hai. Pehle step mein woh poora hai, beech mein ek dashed line hai jahan woh tootega, aur heading kehti hai 1 tukda, 2 poles. Doosre step mein woh do tukdon mein toot kar alag ho gaya hai, har tukde ka ek laal N end aur ek neela S end hai, aur arrows toote hue ends par bane naye poles dikhate hain: 2 tukde, 4 poles. Teesre step mein chaar chhote tukde hain, har ek mein N aur S: 4 tukde, 8 poles.

Quick check
3 mein se 1
Imran bar magnet ko steel pins ke dabbe mein daalta hai aur bahar nikalta hai. Pins zyadatar kaise latkengi?
Answer dekho

Answer (C) Har end par bahut saari aur beech mein bahut kam

Pull poles par sabse strong hota hai, jo dono ends ke paas hain, isliye zyadatar pins wahin latakti hain. Dono poles ek jaisa kheenchte hain, isliye dono ends par kaafi pins hoti hain.

4.3 Directions Pata Karna

Socho, tum school trek par pahadon mein ho. Ghana kohra aa jaata hai aur Sun chhup jaata hai. Camp kis taraf hai? Koi landmark nahi dikh raha. Yahan magnet tumhari madad kar sakta hai. Chalo dekhte hain kaise.

4/4Sun east side se ugta hai, isliye line north–south hai. N end north ki taraf hai.

Fig. 4.7Freely latakta magnet hamesha north–south line par aakar rukta hai.NCERT Fig. 4.5 · p. 65

Upar se dekha gaya farsh ka ek gol hissa, jiske centre mein dhaage se latka bar magnet hai; dhaaga ek chhoti gaanth jaisa dikhta hai aur neeche left se ek label uski taraf ishara karta hai. Pehle step mein magnet tircha hai, upar-left ki taraf, aur mude hue arrows dikhate hain ki woh ghoom raha hai. Doosre step mein woh ghoom kar picture mein seedha upar-neeche ruk gaya hai, N upar hai. Teesre step mein orange crosses aur ek dashed line uske dono ends ki jagah mark karte hain. Chauthe step mein uske chaaron taraf N, S, E aur W directions dikhti hain, aur east side par ugta hua Sun hai.

Ab N aur S naam samajh aate hain. Har pole ka naam us direction par rakha gaya hai jiski taraf woh ghoom jaata hai. Jo end ghoom kar north ki taraf aata hai, woh north-seeking pole hai, ya chhote mein north pole. Uska saathi hamesha south ki taraf rukta hai, isliye woh south-seeking pole hai. Jo magnet freely ghoom sakta hai, woh kabhi kisi aur tarah nahi rukta: woh hamesha north–south line par aakar rukta hai.

Magnet ko ghumata kaun hai? Tum use dekh ya mehsoos nahi kar sakte, lekin poori Earth ek bahut bade magnet ki tarah kaam karti hai! Uska pull har us magnet ko line up kar deta hai jo ghoomne ke liye free hai. Dhaage par latki bar, cork par rakhi needle aur compass ki needle, sab aakhir mein north–south ki taraf point karti hain.

Quick check
3 mein se 1
Freely latakte magnet ka jo end north ki taraf ghoom jaata hai, use uska pole kehte hain.
Answer dekho

Answer north

Yeh magnet ka north-seeking pole, yaani north pole (N), hai.

Magnetic compass

Trek par stand aur latakta magnet le jaana mushkil hoga. Magnetic compass (Hindi mein दिक्सूचक) wahi kaam karta hai aur jeb mein aa jaata hai. Iska dil ek patla, halka, needle jaisa magnet hai. Needle ek pin ki nukeeli tip par tiki hoti hai, isliye aasaani se ghoom sakti hai. Iska north end aam taur par paint kiya hota hai, aksar laal rang se. Needle ke neeche ek card hota hai jise dial kehte hain; us par N, E, S aur W likhe hote hain. Ek transparent lid dhool aur ungliyon ko andar nahi aane deti.

4/4Ab dial ka har mark sahi hai. Gate east mein hai.

Fig. 4.8Needle ko rukne do, box ghumao, phir directions padho.NCERT Fig. 4.6 · p. 66

Ek gol compass jiske dial par N, E, S aur W likhe hain, aur beech ki pin par ek needle jiska painted end laal hai. Pehle step mein needle tirchi hai aur dial aise ghooma hua hai ki uska N ek taraf hai, saath mein note hai ki needle ke rukne ka intezaar karo. Doosre step mein needle picture mein seedha upar point karti hai aur ek label uske painted end ki taraf ishara karta hai, lekin dial ka N abhi bhi right ki taraf hai. Teesre step mein ek muda hua arrow box ko ghumate hue dikhata hai, aur ab dial ka N painted end ke neeche hai. Chauthe step mein East likha ek arrow compass se right mein ek gate ki taraf point karta hai.

  1. Compass ko flat pakdo, iron ki cheezon aur doosre magnets se door.
  2. Needle ke rukne ka intezaar karo.
  3. Box ko dheere-dheere ghumao jab tak dial ka N theek painted end ke neeche na aa jaaye.
  4. Ab dial Earth ke saath line up ho gaya hai. East ke liye E ki taraf dekho, west ke liye W ki taraf, aur isi tarah baaki.
SimulationCompass lab

Upar se dekha gaya ek bar magnet dhaage se freely latka hai aur tab tak jhoolta hai jab tak uska N end north ki taraf na aa jaaye. Uske north mein ek chhota compass bhi north dikhata hai. Tum compass ko kahin bhi drag kar sakte ho: magnet ke paas jaane par needle magnet ke poles ki taraf ghoom jaati hai, aur ek readout batata hai ki woh kis taraf point kar rahi hai.

Fig. 4.9Bar magnet dhaage se freely latka hai. Compass ko uske aas-paas drag karo.
Try karo
  • Play dabao aur latakte magnet ke rukne ka intezaar karo. Uska N end aur compass needle kis taraf point karte hain?
  • Compass ko magnet ke N end ke paas drag karo, phir ghuma kar uske S end tak le jaao. Har pole par painted end kya karta hai?
  • Compass ko magnet ke beech ke theek bagal mein rakh do. Kya needle ab bhi north dikhati hai? To compass ko kahan kabhi use nahi karna chahiye?

4/4Woh ghoom kar north–south line par ruk jaati hai. Tumhara compass taiyaar hai!

Fig. 4.10Stroke, test, float: ghar ka bana compass.NCERT Fig. 4.7 · p. 67

Saare views upar se hain. Pehle step mein ek sewing needle table par padi hai aur ek chhota magnet, S end neeche, uske upar eye se tip tak khisakta hai; ek dashed arrow dikhata hai ki magnet uthakar wapas laaya jaata hai, aur ek label kehta hai 30 se 40 strokes, ek hi taraf. Doosre step mein needle ke dono ends se pins latak rahi hain. Teesre step mein gol cork mein ghusi needle paani ke bowl mein tirchi tair rahi hai. Chauthe step mein woh ghoom kar picture mein seedhi upar-neeche ho gayi hai, N likhe ek arrow ki line mein.

Needle ko ek hi direction mein stroke karna use magnetise karta hai, matlab needle ko magnet bana deta hai. Paani par tairti needle ghoomne ke liye free hoti hai. Isliye woh bilkul latakte bar magnet jaisa behave karti hai aur north–south mein ruk jaati hai.

Quick check
4 mein se 1
Compass use karne ke steps sahi order mein lagao.
  1. Compass ko iron se door flat rakho
  2. Box ghumao jab tak dial ka N painted end ke neeche na aaye
  3. Needle ke rukne ka intezaar karo
  4. Dial se directions padho
Answer dekho
Answer
  1. Compass ko iron se door flat rakho
  2. Needle ke rukne ka intezaar karo
  3. Box ghumao jab tak dial ka N painted end ke neeche na aaye
  4. Dial se directions padho
Pehle needle ko rukna chahiye. Uske baad hi tum dial ko uske hisaab se ghumate ho aur directions padhte ho.

4.4 Magnets ke beech Attraction aur Repulsion

Har haath mein ek magnet pakdo aur unhe paas lao. Kabhi woh tak se uchhal kar jud jaate hain. Ek ko ulta ghuma do, aur ab woh peeche dhakelte hain, jaise unke beech koi invisible spring ho. Chalo iska rule dhoondhein.

3/4B ko ghuma diya, ab uska S end, A ke S end ke saamne hai: A door sarakta hai.

Fig. 4.12Unlike poles paas kheenchte hain, like poles door dhakelte hain, aur iron hamesha khinchta hai.NCERT Fig. 4.8 · p. 68

Upar se dekha gaya paani ka ek rectangular tub, jismein ek gol plastic dhakkan par bar magnet A hai, N left mein aur S right mein. Magnet B tub ke bahar right mein hai. Pehle step mein B halka dikhta hai aur A beech mein hai, saath mein likha hai B ko A ke paas lao. Doosre step mein B ka N end A ke S end ke saamne hai aur A right ki taraf, B ki taraf, tair gaya hai, ek arrow aur label paas khincha ke saath. Teesre step mein B ko aise ghumaya gaya hai ki uska S end A ki taraf hai, aur A left ki taraf, B se door, tair gaya hai, label door dhakela. Chauthe step mein B ki jagah grey iron bar hai, A ko ghuma diya gaya hai taaki uska N end bar ki taraf ho, aur A uski taraf tair gaya hai, label har end se khinchta hai.

Rule yeh hai. Attraction, yaani pull, unlike poles ke beech hota hai: N aur S. Repulsion, yaani push, like poles ke beech hota hai: N aur N, ya S aur S.

SimulationDo-magnet lab

Do bar magnets, A aur B, jinhe tum drag kar sakte ho aur ghuma sakte ho; B ke paas ek flip button bhi hai jo uske poles ki jagah badal deta hai. Arrows dikhate hain ki magnets attract kar rahe hain ya repel. Tum iron filings ya field lines bhi on kar sakte ho, taaki dono magnets ke aas-paas ka pattern dikhe.

Fig. 4.13Magnets ko drag karo, ghumao aur flip karo. Arrows pull ya push dikhate hain.
Try karo
  • B ko A ki taraf khiskao, phir Flip B dabao. Kya badla?
  • A ko uske ⟳ handle se ghumao jab tak A ka S end, B ke S end ke saamne na aa jaaye. Pehle predict karo: woh kheenchenge ya dhakelenge?
  • Iron filings on karo. B ko flip karne par magnets ke beech ka pattern kaise badalta hai?

Magnet hai ya sirf iron?

Iron ke tukde ko magnet ke dono poles kheenchte hain. To agar koi bar tumhare magnet se chipakti hai, to woh magnet bhi ho sakti hai, ya plain iron bhi. Attraction se yeh pata nahi chalta. Repulsion se chalta hai, kyunki sirf magnet hi doosre magnet ke pole ko door dhakel sakta hai. Repulsion hi magnet ka pakka test hai.

Compare

Magnet ya plain iron?

Magnet

  • Iron, nickel aur cobalt ko attract karta hai
  • Freely latkane par north–south mein rukta hai
  • Doosre magnet ke ek pole ko repel karta hai

Plain iron bar

  • Magnet ke dono poles se attract hoti hai
  • Latkane par kisi bhi taraf ruk jaati hai
  • Magnet ko kabhi repel nahi karti
Example

Puzzle: magnet ya iron, bina kisi aur cheez ke

Rohan ke paas do bars hain jo bilkul ek jaisi dikhti hain. Ek magnet hai aur doosri plain iron. Uske paas aur kuch nahi hai, dhaaga bhi nahi. Woh kaise pata kare ki kaun si bar magnet hai?

Pehle khud try karo. Phir solution ek-ek step karke kholo.

3/3Iski jagah S end paas aata hai: painted end paas khincha jaata hai.

Fig. 4.14Compass needle ek chhota magnet hai: like poles use door dhakelte hain, unlike poles use kheenchte hain.NCERT Fig. 4.9 · p. 69

Ek gol compass, jismein north ki dashed line hai aur ek needle jiska painted end laal hai, aur upar-right mein ek bar magnet pada hai. Pehle step mein magnet door hai aur painted end seedha upar, north ki taraf, point karta hai, saath mein ek label hai. Doosre step mein magnet ka N end paas aa gaya hai aur painted end left ki taraf, usse door, ghoom gaya hai, saath mein ek muda arrow aur label N ke paas N: door dhakela. Teesre step mein magnet ka S end compass ki taraf hai aur painted end right ki taraf, uski taraf, ghoom gaya hai, label N ke paas S: paas khincha.

2/4Beech mein lakdi ka board khada hai. Needle ghoomi hui hi rehti hai.

Fig. 4.15Magnet ka pull non-magnetic sheets ke aar-paar chala jaata hai.NCERT Fig. 4.10 · p. 70

Left mein ek compass jismein north ki dashed line hai, aur right mein ek bar magnet jiska S end compass ki taraf hai. Har step mein needle ka painted end magnet ki taraf ghooma hua hai. Pehle step mein dono ke beech kuch nahi hai aur ek label kehta hai needle ghoomi. Doosre step mein dono ke beech lakdi ka ek khada board aata hai, teesre mein cardboard ki sheet, aur chauthe mein glass ki patli sheet; har baar label kehta hai ab bhi ghoomi.

To magnet ka pull non-magnetic materials ke aar-paar kaam karta hai. Isi tarah fridge magnet paper ke aar-paar photo ko pakde rakhta hai. Isi tarah table ke neeche rakha magnet upar rakhi clip ko khiskata hai.

Quick check
4 mein se 1
Do magnets end to end pade hain. Agar aamne-saamne wale ends N aur N hain, to magnets ek-doosre ko karte hain. Agar aamne-saamne ke ends S aur N hain, to woh ek-doosre ko karte hain.
Answer dekho

Answer (1) repel, (2) attract

N–N aur S–S door dhakelte hain (repel); N–S paas kheenchte hain (attract).

4.5 Magnets ke saath Masti

Magnet cheezon ko bina chhue hila sakta hai. Kya yeh thoda jaadu jaisa nahi hai? Baarish wali dopahar ke liye yeh rahe kuch tricks. Inhe try karo, phir apne khud ke tricks banao.

Ab ek twist wali race. Do toy cars mein se har ek ke aage ek chhota magnet tape se chipkao, aise ki same poles aamne-saamne hon. Jab cars milti hain, to kya hota hai? Fig. 4.16 dekho.

3/4Chhod do, aur like poles ke dhakke se woh roll karke door chali jaati hain.

Fig. 4.16Like poles cars ko door dhakelte hain; unlike poles unhe paas kheenchte hain.NCERT Fig. 4.14 · p. 72

Sadak par do toy cars ek-doosre ke aamne-saamne khadi hain, left mein hari aur right mein gulaabi, dono ke aage ek chhota laal-neela magnet hai aur aage ke ends par N likha hai. Pehle step mein woh thodi door hain. Doosre step mein arrows unhe paas dhakelte hain. Teesre step mein woh roll karke bahut door chali gayi hain, beech mein speed lines hain. Chauthe step mein gulaabi car ka magnet ulta kar diya gaya hai taaki uska S end hari car ke N end ke saamne ho, aur dono cars roll karke paas aati hain jab tak unke magnets chhoo na jaayein.

Magnets ka dhyaan rakhna

Agar magnets ke saath laaparwahi ho, to unki strength kam ho sakti hai. Garmi unhe kamzor karti hai. Zor ki chot se bhi woh kamzor hote hain, jaise magnet ko farsh par girana ya hathode se maarna. Strong magnets ko phones se door rakho, aur un cards se bhi jin par kaali magnetic strip hoti hai. Magnet phone ke compass ko confuse kar sakta hai aur strip ki information mita sakta hai.

Magnets sabse lambe samay tak strong rehte hain jab unhe team ki tarah rakha jaaye. Do bar magnets ko ek ke bagal mein ek, ulti directions mein khada karo, taaki N ke paas S ho. Unke beech lakdi ki ek patti rakho. Phir har jodi ke ends ke upar soft iron ki ek chhoti bar rakho, jise keeper kehte hain. Fig. 4.17 yeh step by step dikhata hai.

3/3Soft iron ke do keepers upar ke ends aur neeche ke ends ko jodte hain.

Fig. 4.17Aise rakhne par magnets saalon tak strong rehte hain.NCERT More to know! · p. 73

Do bar magnets ek ke bagal mein ek seedhe khade hain. Left wale ka N upar aur S neeche hai; right wale ka S upar aur N neeche hai, aur upar ek heading kehti hai unlike poles bagal-bagal. Doosre step mein wood likhi lakdi ki ek patti dono ke beech ke gap mein neeche khisakti hai. Teesre step mein keeper likhi do grey iron bars upar ke ends aur neeche ke ends par rakhi jaati hain, jo dono magnets ko chhooti hain.

Quick check
3 mein se 1
Do toy cars ke aage magnets lage hain, S ke saamne S. Paas aane par kya hota hai?
Answer dekho

Answer (B) Woh ek-doosre ko door dhakelti hain

S aur S like poles hain, isliye woh repel karte hain aur cars ko door dhakelte hain.
Flash cards · 15

Yaad rakhne wale words

1 / 15
Recap

Summary aur key points

  1. Magnets magnetic materials jaise iron, nickel, cobalt aur zyadatar steel ko attract karte hain. Wood, plastic, glass, aur copper, aluminium jaise metals non-magnetic hain (Section 4.1).
  2. Magnet apne do poles, north (N) aur south (S), par sabse zyada kheenchta hai, jaisa Fig. 4.4 ki filings dikhati hain (Section 4.2).
  3. Poles hamesha jodi mein aate hain: toote magnet ke har tukde mein N aur S dono hote hain (Fig. 4.6).
  4. Magnets kai shapes mein aate hain, jaise bar, U-shaped aur ring, aur har ek ke do poles hote hain (Fig. 4.5).
  5. Freely latakta magnet north–south mein rukta hai, kyunki poori Earth ek bahut bade magnet ki tarah kaam karti hai (Section 4.3).
  6. Magnetic compass directions pata karne ke liye freely ghoomne wali magnetised needle use karta hai (Fig. 4.8).
  7. Steel needle ko ek hi direction mein kai baar stroke karne se woh magnetise ho jaati hai; paani par tairane par woh compass ban jaati hai (Activity 4.4).
  8. Like poles repel karte hain aur unlike poles attract karte hain (Section 4.4).
  9. Iron ko dono poles kheenchte hain, isliye sirf repulsion hi saabit karta hai ki koi cheez magnet hai (Magnet ya iron?).
  10. Magnet ka pull non-magnetic materials jaise wood, cardboard aur glass ke aar-paar jaata hai (Activity 4.7).
  11. Garmi aur chot magnets ko kamzor karti hain; unhe jodi mein, ends par keepers lagakar rakho (Fig. 4.17).
Practice · 15 questions

Practice questions answers ke saath (NCERT “Chalo, apni samajh aur badhayein”)

  1. Short answerEasyNCERT Exercises Q1

    Blanks bharo.

    1. Ek magnet ka N end doosre magnet ke S end ke paas rakho, to woh ek-doosre ko karte hain.

      Answer dekho

      Answer attract

      N aur S unlike poles hain, aur unlike poles attract karte hain.

    2. Rubber eraser, glass marble aur copper wire, sab materials hain.

      Answer dekho

      Answer non-magnetic

      Magnet rubber, glass ya copper ko nahi kheenchta.

    3. Akele chhod do, to compass needle ka painted end ki taraf point karta hai.

      Answer dekho

      Answer north

      Painted end needle ka north pole hai, isliye woh north ki taraf point karta hai.

    4. Magnet ko kitni bhi baar todo, har tukde ke poles hote hain.

      Answer dekho

      Answer two

      Poles hamesha jodi mein aate hain, isliye har tukde ka ek N aur ek S pole hota hai.
  2. Short answerEasyNCERT Exercises Q2

    Sahi ya galat?

    1. Bar magnet ko aadha kaato, to ek aadhe mein sirf north pole hota hai.

      Answer dekho

      Answer Galat

      Har aadhe ko N aur S dono poles milte hain.

    2. Do south poles ek-doosre ko paas kheenchte hain.

      Answer dekho

      Answer Galat

      Do south poles like poles hain, isliye woh repel karte hain.

    3. Jab bar magnet ko pins ke dher se uthate hain, to zyadatar pins uske dono ends se latakti hain.

      Answer dekho

      Answer Sahi

      Pull poles par sabse strong hota hai, jo ends ke paas hain.

    4. Dhaage se freely latakta bar magnet east–west direction mein rukta hai.

      Answer dekho

      Answer Galat

      Woh north–south direction mein rukta hai.
  3. Short answerEasyNCERT Exercises Q3

    Har line poori karo: kya hota hai, ya kaun sa pole missing hai?

    1. S ke saamne S ho, to milta hai…

      Answer dekho

      Answer (B) repulsion

      S aur S like poles hain, isliye woh repel karte hain.

    2. N ke saamne kaun sa pole ho, to attraction hota hai?

      Answer dekho

      Answer (B) S

      Sirf unlike pole, S, N ko attract karta hai.

    3. N ke saamne S ho, to milta hai…

      Answer dekho

      Answer (A) attraction

      N aur S unlike poles hain, isliye woh attract karte hain.

    4. N ke saamne kaun sa pole ho, to repulsion hota hai?

      Answer dekho

      Answer (A) N

      Sirf like pole, N, N ko repel karta hai.
  4. Quick answerMediumNCERT Exercises Q4

    Kavya steel pins ki tray se bar magnet uthati hai. Woh ginti hai ki left end par 12 pins latak rahi hain aur beech mein sirf 1. Right end par lagbhag kitni pins latak rahi hongi?

    Answer dekho

    Answer (B) lagbhag 12

    Dono ends poles hain, aur bar magnet ke dono poles lagbhag barabar kheenchte hain. Isliye right end par bhi left jitni, lagbhag 12, pins hongi. Beech mein pull kamzor hai, isliye wahan bahut kam pins hain; to "lagbhag 1" beech ke liye sahi hai, kisi end ke liye nahi.
  5. Short answerMediumNCERT Exercises Q5

    Anil ko chaar bars milti hain, W, X, Y aur Z, jo bilkul ek jaisi dikhti hain. Teen magnets hain aur ek plain iron hai. Woh do-do karke test karta hai aur note karta hai: W aur X ek tarah pakadne par door dhakelte hain. Y aur Z hamesha sirf paas kheenchte hain, chahe woh unhe kaise bhi pakde. W aur Y ek tarah pakadne par door dhakelte hain.

    1. Plain iron wali bar kaun si hai?

      Solution dikhao
      1. W aur X ne ek-doosre ko door dhakela. Sirf do magnets hi repel kar sakte hain, isliye W aur X dono magnets hain.
      2. W aur Y ne bhi door dhakela, isliye Y bhi magnet hai.
      3. To teen magnets ho gaye: W, X aur Y. Isliye Z plain iron ki bar hai.
      4. Isse yeh bhi samajh aata hai ki Y aur Z hamesha sirf paas kyun khinche: magnet iron ko hamesha attract karta hai.

    2. Anil ka dost kehta hai, "Y aur Z paas khinche, isliye Z zaroor magnet hai." Is idea mein kya galat hai?

      Solution dikhao

      AnswerMagnet plain iron ko bhi kheenchta hai, isliye pull se saabit nahi hota ki Z magnet hai. Yeh sirf push se saabit hota hai.

      Pull unlike poles ke beech hota hai, lekin magnet aur plain iron ke tukde ke beech bhi hota hai. To jab Y, Z ko kheenchta hai, Z kuch bhi ho sakta hai. Push ke liye do magnets chahiye, isiliye repulsion hi magnet ka pakka test hai.

  6. Short answerEasyNCERT Exercises Q6

    Zara ke bar magnet par N aur S ke marks mit gaye hain. Woh uske dono ends ko X aur Y kehti hai. Woh ek dost ke magnet ka marked S pole end X ke paas laati hai, aur end X door dhakela jaata hai.

    1. End X kaun sa pole hai?

      Answer dekho

      Answer (B) south pole

      S pole sirf doosre S pole ko door dhakelta hai, isliye X south pole hai.

    2. End Y kaun sa pole hai?

      Answer dekho

      Answer (A) north pole

      Magnet ke dono ends hamesha alag poles hote hain, isliye Y north pole hai.

    3. Maan lo end X marked S pole ki taraf khinch jaata. Tab X kya hota?

      Solution dikhao

      Hum pehle se jaante hain ki Zara ki bar magnet hai. Do magnets ke beech pull sirf unlike poles mein hota hai. Marked pole S hai, isliye X, N hota. Aur pakka karne ke liye S pole ko doosre end ke paas bhi lao: use woh end door dhakelna chahiye.

  7. Short answerMediumNCERT Exercises Q7

    Camp mein tumhe bina marks wala ek bar magnet milta hai. Tumhare paas thoda dhaaga hai aur subah ka saaf aasmaan, lekin koi doosra magnet ya compass nahi. Tum kaise pata karoge ki kaun sa end uska north pole hai?

    Solution dikhao

    AnswerUse freely latkao; jo end north ki taraf aakar rukta hai, woh north pole hai.

    Dhaage ko beech mein baandho taaki magnet seedha latke, iron ki cheezon se door. Use rukne do: woh north–south mein rukega. Ugte Sun ki taraf mooh karo, jo lagbhag east hai; tab north tumhare left mein hoga. Magnet ka jo end us taraf hai, woh uska north pole hai.

  8. Short answerHardNCERT Exercises Q8

    Compass needle ka north pole Earth ke geographic north ki taraf point karta hai. Socho ki Earth ek bahut bada bar magnet hai. Geographic north ke paas Earth ke magnet ka kaun sa magnetic pole, N ya S, hona chahiye? Samjhao.

    Solution dikhao

    AnswerSouth (S) magnetic pole.

    Unlike poles attract karte hain. Needle ka N pole north ki taraf khinchta hai. To Earth ke magnet ka S pole geographic north ke paas hona chahiye, aur N pole geographic south ke paas. Yeh sunkar bahut log hairaan hote hain: jis jagah ko hum North Pole kehte hain, uske paas Earth ke magnet ka south pole hai.

  9. Short answerMediumNCERT Exercises Q9

    Meena ki steel ki sewing needle farsh ki do tiles ke beech ki patli daraar mein gir gayi hai. Uska bar magnet itna mota hai ki daraar mein nahi jaata. Uske paas ek lambi, patli iron nail bhi hai. Is chapter mein jo seekha, uski madad se woh needle kaise nikaal sakti hai?

    Solution dikhao

    AnswerNail ko magnet banao, phir uski tip daraar mein daal kar needle utha lo.

    Nail ko bar magnet ke ek pole se 30 se 40 baar stroke karo, hamesha head se tip ki taraf. Har stroke ke baad magnet ko upar utha lo, jaise Activity 4.4 mein. Nail magnet ban jaati hai. Ab uski tip daraar mein khiskao: steel ki needle usse chipak kar bahar aa jaati hai. Ek aur tareeka hai bar magnet ko nail ke head se laga kar rakhna. Jab tak woh chhoo rahe hain, nail magnet ki tarah kaam karti hai, bilkul paper-clip chain ki tarah.

  10. Short answerHardNCERT Exercises Q10

    Ravi teen ring magnets ko ek khadi pencil mein daalta hai. Sabse neeche wali ring table par tiki hai. Beech wali ring uske upar hawa mein tairti hai, aur upar wali ring beech wali ke upar tairti hai. Neeche wali ring ka upar wala face uska N pole hai.

    1. Beech wali ring neeche wali ring par gir kyun nahi jaati?

      Solution dikhao

      AnswerDono rings ke aamne-saamne wale faces like poles hain, isliye woh repel karte hain.

      Beech wali ring ka neeche wala face, neeche wali ring ke upar wale face ke saamne hai. Dono ek-doosre ko door dhakelte hain, isliye woh like poles hone chahiye. Yahi push beech wali ring ko uske weight ke khilaaf upar rokta hai.

    2. Beech wali ring ka neeche wala face: . Beech wali ring ka upar wala face: .

      Answer dekho

      Answer (1) N, (2) S

      Beech wali ring ko ek N face upar dhakel raha hai, isliye uska neeche wala face N hai (like poles repel karte hain). Ring ke dono faces ulte poles hote hain, isliye uska upar wala face S hai.

    3. Ravi upar wali ring ko beech wali ring par kaise bitha sakta hai, bina use neeche dabaye?

      Solution dikhao

      AnswerUpar wali ring nikaalo, use ulta karo aur wapas daal do.

      Upar wali ring beech wali ring ke S face ke upar tair rahi hai, isliye uska neeche wala face S hona chahiye. Ulta karne par uska N face neeche aa jaata hai. N aur S attract karte hain, isliye upar wali ring neeche khinchti hai aur beech wali ring par chipak kar baith jaati hai.

  11. DiagramHardNCERT Exercises Q11

    Teen bar magnets table par U shape mein rakhe hain, jaise figure mein, aur corners par chipke rehte hain. End 6 par N likha hai. Har end ka pole pata karo. End 1: , end 2: , end 3: , end 4: , end 5: .

    Fig. 4.18U mein teen bar magnets. Sirf end 6 par mark hai.

    Teen grey bar magnets U shape banate hain. Left wala magnet khada hai, end 1 upar aur end 2 neeche. Neeche wala magnet leta hua hai, uska left end 3 left magnet ko chhoota hai aur right end 4 right magnet ko. Right wala magnet khada hai, end 5 neeche aur end 6 upar, jis par N likha hai.

    Solution dikhao
    1. End 6 N hai, isliye usi magnet ka doosra end, end 5, S hai.
    2. End 4, end 5 ko chhoota hai aur magnets chipke rehte hain, yaani woh attract karte hain: end 4 N hai.
    3. End 3 neeche wale magnet ka doosra end hai, isliye woh S hai.
    4. End 2, end 3 ko chhoota hai, isliye woh N hai.
    5. End 1 left magnet ka doosra end hai, isliye woh S hai.
  12. Quick answerEasy

    Magnet inmein se kise nahi kheenchega?

    Answer dekho

    Answer (C) copper ka sikka

    Copper non-magnetic metal hai. Steel, iron aur nickel sab magnetic hain.
  13. Quick answerEasy

    Har woh material chuno jo non-magnetic hai.

    Saare sahi options chuno
    Answer dekho
    Answer
    • (A) wood
    • (B) aluminium
    • (D) glass
    Wood, aluminium aur glass non-magnetic hain. Iron aur nickel magnetic hain.
  14. Quick answerMedium

    Needle compass banane ke steps order mein lagao.

    1. Check karo ki needle ab pins uthati hai
    2. Cork ko paani par tairao aur rukne do
    3. Needle ko ek pole se, ek hi taraf, 30 se 40 baar stroke karo
    4. Needle ko cork ke tukde ke aar-paar ghusao
    Answer dekho
    Answer
    1. Needle ko ek pole se, ek hi taraf, 30 se 40 baar stroke karo
    2. Check karo ki needle ab pins uthati hai
    3. Needle ko cork ke tukde ke aar-paar ghusao
    4. Cork ko paani par tairao aur rukne do
    Pehle magnetise karo, use test karo, phir needle ko cork par lagao aur tairao, taaki woh freely ghoom sake.
  15. Quick answerMedium

    Har magnet ko uske poles ki jagah se match karo.

    Left mein koi item tap karo, phir right mein uska match.

    Answer dekho
    Answer
    • Bar magnet : har end par ek pole, door-door
    • U-shaped magnet : dono poles paas-paas, tips par
    • Ring magnet : har chapte face par ek pole
    Poles wahan hote hain jahan pull sabse strong hota hai. Bar mein woh dono ends hain, door-door. U mein dono tips, paas-paas. Ring mein dono chapte faces.

Apna NCERT exercise question dhoondo

Hamare practice questions ncert.ai ke liye likhe gaye hain aur NCERT exercises ko follow karte hain. Apni textbook ke question se match karne wala question dhoondo; uska answer uske saath hai.

Tumhari NCERT textbook meinYahan practice question
NCERT Exercises Q1Practice Q1
NCERT Exercises Q2Practice Q2
NCERT Exercises Q3Practice Q3
NCERT Exercises Q4Practice Q4
NCERT Exercises Q5Practice Q5
NCERT Exercises Q6Practice Q6
NCERT Exercises Q7Practice Q7
NCERT Exercises Q8Practice Q8
NCERT Exercises Q9Practice Q9
NCERT Exercises Q10Practice Q10
NCERT Exercises Q11Practice Q11

Quick check: MCQs

  1. 4.1 Magnetic aur Non-magnetic Materials3 questions
  2. Kya magnet ka sirf ek pole ho sakta hai?3 questions
  3. 4.3 Directions Pata Karna3 questions
  4. Magnetic compass4 questions
  5. Magnet hai ya sirf iron?4 questions
  6. Magnets ka dhyaan rakhna3 questions
Glossary · 15

Key terms (English + Hindi)

attractionआकर्षणaakarshan
Ek pull jo do cheezon ko paas laata hai, jaise unlike poles ke beech, ya magnet aur iron ke beech.Chapter mein pehli baar yahan aaya →
bar magnetछड़ चुंबकchhad chumbak
Seedhi, chapti bar jaisa magnet, jiske har end par ek pole hota hai.Chapter mein pehli baar yahan aaya →
iron filingsलोहे का बुरादाlohe ka buraada
Iron ke bahut chhote tukde, mote kaale powder jaise, jinse dikhta hai ki magnet kahan sabse zyada kheenchta hai.Chapter mein pehli baar yahan aaya →
lodestoneप्राकृतिक चुंबकprakritik chumbak
Nature mein milne wala patthar jo pehle se hi magnet hota hai. Factory mein magnets banne se bahut pehle log lodestones use karte the.Chapter mein pehli baar yahan aaya →
magnetचुंबकchumbak
Aisi cheez jo iron, nickel ya cobalt se bani cheezon ko apni taraf kheenchti hai. Har magnet ke do poles hote hain.Chapter mein pehli baar yahan aaya →
magnetic compassचुंबकीय दिक्सूचकchumbakiya diksoochak
Chhota device jismein magnetised needle freely ghoomti hai aur north–south mein rukti hai; isse directions pata karte hain.Chapter mein pehli baar yahan aaya →
magnetic materialचुंबकीय पदार्थchumbakiya padarth
Aisa material jise magnet attract karta hai, jaise iron, nickel, cobalt ya zyadatar tarah ke steel.Chapter mein pehli baar yahan aaya →
magnetiseचुंबकित करनाchumbakit karna
Iron ya steel ke tukde ko magnet bana dena, jaise use ek hi direction mein magnet se kai baar stroke karke.Chapter mein pehli baar yahan aaya →
non-magnetic materialअचुंबकीय पदार्थachumbakiya padarth
Aisa material jise magnet attract nahi karta, jaise wood, plastic, glass, copper ya gold.Chapter mein pehli baar yahan aaya →
north pole (magnet ka)उत्तरी ध्रुवnorth pole (of a magnet)uttari dhruv
Freely latakte magnet ka woh end jo ghoom kar north ki taraf aa jaata hai; ise north-seeking pole (N) bhi kehte hain.Chapter mein pehli baar yahan aaya →
poleध्रुवdhruv
Magnet ki woh jagah jahan uska pull sabse strong hota hai. Har magnet ka ek north pole aur ek south pole hota hai.Chapter mein pehli baar yahan aaya →
repulsionप्रतिकर्षणpratikarshan
Ek push jo do cheezon ko door karta hai, jaise do like poles ke beech.Chapter mein pehli baar yahan aaya →
ring magnetवलय चुंबकvalay chumbak
Chapta, gol magnet jiske beech mein ched hota hai. Uske do chapte faces hi uske poles hain.Chapter mein pehli baar yahan aaya →
south pole (magnet ka)दक्षिणी ध्रुवsouth pole (of a magnet)dakshini dhruv
Freely latakte magnet ka woh end jo ghoom kar south ki taraf aa jaata hai; ise south-seeking pole (S) bhi kehte hain.Chapter mein pehli baar yahan aaya →
U-shaped magnetनाल चुंबकnaal chumbak
Letter U ki shape mein muda hua magnet, jiske dono poles uski tips par hote hain.Chapter mein pehli baar yahan aaya →

Tum chapter ke end tak pahunch gaye