Magnetics Ques 24
- A proton moving with a constant velocity passes through a region of space without any change in its velocity. If $E$ and $B$ represent the electric and magnetic fields respectively. Then, this region of space may have
$(1985,2 M)$
(a) $E=0, B=0$
(b) $E=0, B \neq 0$
(c) $E \neq 0, B=0$
(d) $E \neq 0, B \neq 0$
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Answer:
Correct Answer: 24.$(a, b, d)$
Solution:
Formula:
Magnetic Force Acting On A Moving Point Charge:
- If both $E$ and $B$ are zero, then $\mathbf{F} _e$ and $\mathbf{F} _m$ both are zero. Hence, velocity may remain constant.
Therefore, option (a) is correct.
If $E=0, B \neq 0$ but velocity is parallel or antiparallel to magnetic field, then also $\mathbf{F} _e$ and $\mathbf{F} _m$ both are zero.
Hence, option (b) is also correct.
If $E \neq 0, B \neq 0$ but $\mathbf{F} _e+\mathbf{F} _m=0$, then also velocity may remain constant or option
(d) is also correct.
BETA
