JEE MAIN - Physics (2024 - 27th January Morning Shift - No. 4)
A proton moving with a constant velocity passes through a region of space without any change in its velocity. If $$\overrightarrow{\mathrm{E}}$$ and $$\overrightarrow{\mathrm{B}}$$ represent the electric and magnetic fields respectively, then the region of space may have :
(A) $$\mathrm{E}=0, \mathrm{~B}=0$$
(B) $$\mathrm{E}=0, \mathrm{~B} \neq 0$$
(C) $$\mathrm{E} \neq 0, \mathrm{~B}=0$$
(D) $$\mathrm{E} \neq 0, \mathrm{~B} \neq 0$$
Choose the most appropriate answer from the options given below :
Explanation
Net force on particle must be zero i.e. $$\mathrm{q} \overrightarrow{\mathrm{E}}+\mathrm{q} \overrightarrow{\mathrm{V}} \times \overrightarrow{\mathrm{B}}=0$$
Possible cases are
(i) $$\overrightarrow{\mathrm{E}} \& \overrightarrow{\mathrm{B}}=0$$
(ii) $$\overrightarrow{\mathrm{V}} \times \overrightarrow{\mathrm{B}}=0, \overrightarrow{\mathrm{E}}=0$$
(iii) $$q \overrightarrow{\mathrm{E}}=-\mathrm{q} \overrightarrow{\mathrm{V}} \times \overrightarrow{\mathrm{B}}$$
$$\overrightarrow{\mathrm{E}} \neq 0 \& \overrightarrow{\mathrm{B}} \neq 0$$
Comments (0)
