Question

Solve previous year Question of iit jee
chapter :- magnetic effect of current​

Answer 1

Answer:

Option :- (B)

Explanation:

When magnet is divided into two equal parts , the magnetic dipole moment

M' = pole strength × L/2 = M/2 [Pole strength remains same ]

also, the mass of magnetic becomes half i.e m'= ,m/2

moment of inertia of magnet ,I = ml²/12

new moment of inertia ,I' = 1/12(m/2)² (l/2)² = ml²/12 ×8

• ∴ I' = I/8

• Now, T = 2π √I/MB

• T' = 2π √I'/MB = 2π √ I/8 /MB/2

• T' = T/2

• → T'/T = 1/2 Answer .