A 1 m long metal rod XY completes the circuit as shown in figure. The plane of the circuit is perpendicular to the magnetic field of flux density 0.15 T. If the resistance of the circuit is 5 Ω, the force needed to move the rod in direction, as indicated, with a constant speed of 4 m/s will be ____________ 10 -3 N. Numerical answer type. Work it out, then open the answer.

Answer: 18. e = Blv = 0.15 × 1 × 4 = 0.6 V I = e/R = 0.6/5 = 0.12 A F = BIl = 0.15 × 0.12 × 1 = 0.018 N So F = 18 × 10⁻³ N, answer 18.

A 1 m long metal rod XY completes the circuit as shown in figure. The… | JEE Main 2023 (10 Apr, Shift 1)

Q32JEE Main 2023 · 10 APR · SHIFT 1Medium

Motional EMF

A 1 m long metal rod XY completes the circuit as shown in figure. The plane of the circuit is perpendicular to the magnetic field of flux density 0.15 T. If the resistance of the circuit is 5 $\Omega$ , the force needed to move the rod in direction, as indicated, with a constant speed of 4 m/s will be ____________ 10 $-3$ N.

Numerical answer type. Work it out, then open the answer.

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Answer: 18

$e = Blv = 0.15 \times 1 \times 4 = 0.6\text{ V}$
$I = \dfrac{e}{R} = \dfrac{0.6}{5} = 0.12\text{ A}$
$F = BIl = 0.15 \times 0.12 \times 1 = 0.018\text{ N}$
So $F = 18 \times 10^{-3}\text{ N}$ , answer 18.

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