JEE Mains · Physics · STD 12 - Moving charges and magnetism
- JEE Mains 2024
- Hard
- MCQ
A proton moving with a constant velocity passes through a region of space without any change in its velocity. If \(\vec{E}\) and \(\vec{B}\) 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 :
Pick an option to check your answer.
Answer & Solution
Correct Answer
(C) \((A)\), \((B)\) and \((D)\) only
Step-by-step Solution
Detailed 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
\((i)\) \(\overrightarrow{\mathrm{E}} \& \overrightarrow{\mathrm{B}}=0\)
\((ii)\) \(\overrightarrow{\mathrm{V}} \times \overrightarrow{\mathrm{B}}=0, \overrightarrow{\mathrm{E}}=0\)
\((iii)\) \(\mathrm{q} \overrightarrow{\mathrm{E}}=-\mathrm{q} \overrightarrow{\mathrm{V}} \times \overrightarrow{\mathrm{B}}\)
\(\overrightarrow{\mathrm{E}} \neq 0 \& \overrightarrow{\mathrm{B}} \neq 0\)
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