AP EAPCET 04-Jul-2022 Shift 2 Paper

(a) No. of turns in circular coil, N=100
Radius, r=3‌cm=3×10−2m
Resistance, R=4Ω.
No. of turns per unit length in the solenoid,
n=200 turns ∕cm=20000 turns ∕m
∵ Magnetic field inside the solenoid, B=µ0nI
Hence, induced emf
e‌=‌

Nd

dt

BA
‌=‌

Nd

dt

µ0nIA=Nµ0nA‌

dI

dt

‌=100×4π×10−7×20000×πr2(‌

2−0

0.04

)
‌=4π×10−7×2×106×π×(2×10−2)2×50
Induced current, ‌I=‌

e

R

=‌

4π×10−7×2×106×π×(2×10−2)2×50

4

=4π2‌mA.