Question

A frame $\text{CDEF}$ is placed in a region where a magnetic field $\overrightarrow{B}$ is into the plane of the loop. A rod of length $1\text{m}$ moves with constant velocity $20{\text{ms}}^{-1}$ and strength of magnetic field is $1\text{T}$. The power delivered in the process is-

[The value of $R=0.2\Omega$ and other parts have negligible resistance]

• A. $4\text{kW}$
• B. $3\text{kW}$
• C. $2\text{kW}$
• D. $1\text{kW}$

Answer 1

The correct option is C $2\text{kW}$

Given, $v=20{\text{ms}}^{-1};B=1\text{T}l=1\text{m};R=0.2\Omega$

Power delivered is,

$P=Fv=\frac{B^2{l}^2{v}^2}{R}$= $\frac{1^2\times 1^2\times {20}^2}{0.2}$

$=\frac{4000}{2}=2000\text{W}\text{(or)}$

$P=2\text{kW}$

<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}--> Hence, $\left(C\right)$ is the correct answer.