Exams › JEE Main › Physics
Two coils A and B have a mutual inductance M = 2 H. The magnetic flux through coil A changes by 4 Wb in 10 s because of a changing current in coil B. Which statement is correct?
- the change in current in B during this interval is 0.5 A
- the change in current in B during this interval is 2 A
- the change in current in B during this interval is 8 A
- a change of 1 A in coil A's current changes the flux through B by 4 Wb
Correct answer: the change in current in B during this interval is 2 A
Solution
Mutual inductance relates the flux through one coil to the current in the other: phi_A = M I_B, so Delta(phi_A) = M Delta(I_B). Then Delta(I_B) = Delta(phi_A)/M = 4/2 = 2 A. Option 4 is wrong because a 1 A change in A's current would change flux through B by M*1 = 2 Wb, not 4 Wb.
Related JEE Main Physics questions
- A metallic ring is kept in a horizontal position, and a bar magnet is released so that it falls through the ring with its length aligned along the ring’s axis. The magnet’s acceleration while falling is
- A coil has resistance 10 Ω, and the magnetic flux linked with it changes with time according to ϕ = 4t² + 2t + 1 (in weber). The current induced in the coil at t = 1 s is
- Two coils are kept near one another. The mutual inductance of the coil pair depends on
- A conducting rod of length ℓ is attached to a string of length 2ℓ and is rotated on a horizontal table about the fixed end of the string with angular speed ω. If a uniform magnetic field B acts vertically through the region, what is the induced emf between the two ends of the rod?
- A pair of coils, each having N turns, has mutual inductance M henry. If the current in one coil changes from 1 ampere to zero in time t seconds, what is the induced emf per turn in the other coil, in volts?
- A boat travels straight toward the east in a place where Earth’s magnetic field is horizontal, points due north, and has magnitude 5.0 × 10⁻⁵ N A⁻¹ m⁻¹. A 2 m long vertical antenna is mounted on the boat. If the boat’s speed is 1.50 m s⁻¹, what emf is induced across the antenna wire?
⚔️ Practice JEE Main Physics free + battle 1v1 →