Target Exam

CUET

Subject

Physics

Chapter

Moving Charges and Magnetism

Question:

A rectangular coil of sides 2 cm and 5 cm having 2000 turns and carrying a current of 200 mA is placed in a uniform magnetic field of 5.0 T directed along positive X-axis. The maximum torque experienced by the coil is

Options:

2 N m

4 N m

0.2 N m

0.4 N m

Correct Answer:

2 N m

Explanation:

The correct answer is Option (1) → 2 N m

Given:

Length $l = 5$ cm = 0.05 m

Width $w = 2$ cm = 0.02 m

Number of turns $N = 2000$

Current $I = 200$ mA = 0.2 A

Magnetic field $B = 5$ T

Area of one turn: $A = l \times w = 0.05 \times 0.02 = 0.001$ m²

Maximum torque: $\tau_\text{max} = N I A B$

$\tau_\text{max} = 2000 \times 0.2 \times 0.001 \times 5$

$\tau_\text{max} = 2$ N·m

Answer: $\tau_\text{max} = 2$ N·m