A uniform magnetic field B exists in a cylindrical region of radius 10 cm. A wire of length 80 cm and resistance 40 Ω is bent into a square frame and placed with one side along a diameter of the cylindrical region. If B increases at 0.1 T s⁻¹, the induced current is:

Question

G1 Physics · Accepted Answer

Magnetic flux is Φ=∫B⃗·dA⃗ and induced emf is ε=-dΦ/dt. Apply Lenz’s law for direction and I=ε/R when the circuit is resistive. This gives 3.9 × 10⁻⁵ A.