Question

A conducting loop in the shape of a right angled isosceles triangle of height 10 cm is kept such that the 90° 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 a constant rate of 10 A s ^-1 . Which of the following statement(s) is(are) true?

(A) The magnitude of induced emf in the wire is (μ₀/π) volt

(B) If the loop is rotated at a constant angular speed about the wire, an additional emf of (μ₀/π) volt is induced in the wire 

(C) The induced current in the wire is in opposite direction to the current along the hypotenuse 

(D) There is a repulsive force between the wire and the loop

Answer 1

(A) The magnitude of induced emf in the wire is (μ₀/π) volt

(D) There is a repulsive force between the wire and the loop

Due to rotation there is no change in flux through the wire, so there is no extra induced emf in the wire. From Lenz’s Law, current in the wire is rightward so repulsive force acts between the wire and loop.