Magnetism> Interesting ques..Interesting ques..A cir...

Interesting ques..Interesting ques..A circular conductin loop of radius r0 &having resistance per unit length is placed vertically in magnetic field B which is constant in space &time.The ends of the loop are crossed and pulled in opposite directions with velo v such dat the loop always remain circular and the radius of the loop goes on decreasing..then1)radius of loop changes with time t as???2)Find the current induced in the loop..

Navjyot Kalra , 10 Years ago

Grade 10

2 Answers

ROSHAN MUJEEB

Last Activity: 4 Years ago

Perimeter is decreasing at a rate of 2v
ddt(2πr)=2v⇒drdt=vπ
∴r=(r0−vπt)
ϕ=Bπr2⇒ɛ=∣∣∣−dϕdt∣∣∣=B2πrdrdt
∴ɛ=2Bπ(r0−vπt)vπ=2Bv(r0−vπt)
I=ϕR=2Bvrλ.2πr=Bvπλ

ROSHAN MUJEEB

Last Activity: 4 Years ago

Perimeter is decreasing at a rate of 2v
ddt(2πr)=2v⇒drdt=vπddt(2πr)=2v⇒drdt=vπ
∴r=(r0−vπt)∴r=(r0-vπt)
ϕ=Bπr2⇒ɛ=∣∣∣−dϕdt∣∣∣=B2πrdrdtϕ=Bπr2⇒ɛ=|-dϕdt|=B2πrdrdt
∴ɛ=2Bπ(r0−vπt)vπ=2Bv(r0−vπt)∴ɛ=2Bπ(r0-vπt)vπ=2Bv(r0-vπt)
I=ϕR=2Bvrλ.2πr=Bvπλ