A conducting circular loop rotates with angular speed 100 rad/s in magnetic field 0.5 T. When rotated by 30°, induced EMF is 15.4 mV. Find radius of loop.
Solution:
Induced EMF:
E = BAω sinθ
Where:
15.4 × 10-3 = 0.5 × A × 100 × (1/2)
15.4 × 10-3 = 25A
A = 6.16 × 10-4 m2
For circular loop:
A = πr2
r = √(A/π)
r = √[(6.16 × 10-4)/π]
r ≈ 1.4 × 10-2 m
r ≈ 1.4 cm
Answer: 1.4 cm