Magnetics Ques 125
- A metallic block carrying current $I$ is subjected to a uniform magnetic induction $\mathbf{B}$ as shown in figure. The moving charges experience a force $\mathbf{F}$ given by …… which results in the lowering of the potential of the face……. Assume the speed of the charges to be $v$.
$(1996,2 M)$
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Answer:
Correct Answer: 125.$(e v B \hat{\mathbf{k}}, ABCD)$
Solution:
Formula:
Magnetic Force Acting On A Moving Point Charge:
In metals, charge carries are free electrons. Current is in positive direction of $x$-axis. Therefore, charge carries will be moving in negative direction of $x$-axis.
$ \begin{aligned} \mathbf{F} _m=q(\mathbf{v} \times \mathbf{B}) & =(-e)(-v \hat{\mathbf{i}}) \times(B \hat{\mathbf{j}}) \\ \mathbf{F} _m & =e v B \hat{\mathbf{k}} \end{aligned} $
Due to this magnetic force, electrons will be collecting at face $A B C D$, therefore lowering its potential.
BETA
