Question

A metal rod of length 1 m is rotated about one of its ends in a plane perpendicular to a magnetic field of induction 2.5 × 10⁻³Wb/m². If it makes 1800 revolutions per minute, calculate the emf induced between its ends.

• A. 2.471 V
• B. 3.171 V
• C. 0.471 V
• D. 1.771 V

Hint:

Rotational emf depends on angular speed and square of rod length.

Answer 1

The Correct Option is C

Step 1: Formula for induced emf. For a rotating rod: = (1)/(2) B ω l²
Step 2: Converting angular speed. ω = (2π × 1800)/(60) = 60π rad/s
Step 3: Substituting values. = (1)/(2) × 2.5×10⁻³ × 60π × 1² ≈ 0.471V