JEE Advanced2016PhysicsElectromagnetic InductionActual
A conducting loop in the shape of right angled isosceles triangle of height 10 cm is kept such that the 90 o vertex is very close to an infinitely long conducting wire (see the figure). The wire is electrically insulated from the loop. The hypotenuse of the triangle is parallel to the wire. The current in the triangular loop is in counterclockwise direction and increased at constant rate of 10 A s - 1 . Which of the
Options
- AThe induced current in the wire is in opposite direction to the current along the hypotenuse.
- BThere is a repulsive force between the wire and the loop
- CIf the loop is rotated at a constant angular speed about the wire, an additional emf of μ 0 π volt is induced
- DThe magnitude of induced emf in the wire is μ 0 π volt
Correct answer
B. There is a repulsive force between the wire and the loop
Step-by-step solution
From lenz's law it can be understood that due to induced current in wire flux will change in loop thats why it will be repelled by the loop Also by direction of induced electric field, the current in the wire is in the same direction of current along the hypotenuse. Flux through triangle if wire has current i 1 ϕ 2 = ∫ 0 0 . 1 B d A = ∫ 0 0.1 μ 0 i 1 2 π x 2 x d x = μ 0 i 1 10 π ⇒ ϕ 2 = M i 1 ⇒ Mutual inductance M = μ 0 10 π Induced emf in wire ε 1 = M d i 2 d t = μ 0 10 π d i 2 d t = μ 0 10 π × 10 = μ 0 π