JEE Mains · Physics · STD 12 - 4. Moving charges and magnetism
In a certain region static electric and magnetic fields exist. The magnetic field is given by \(\vec B = {B_0}\left( {\hat i + 2\hat j - 4\hat k} \right)\). If a test charge moving with a velocity \(\vec v = {v_0}\left( {3\hat i - \hat j + 2\hat k} \right)\) experiences no force in that region, then the electric field in the region, in \(SI\, units\), is
- A \(\vec E = - {v_0}{B_0}\left( {3\hat i - 2\hat j - 4\hat k} \right)\)
- B \(\vec E = - {v_0}{B_0}\left( {\hat i + \hat j + 7\hat k} \right)\)
- C \(\vec E = {v_0}{B_0}\left( {14\hat j + 7\hat k} \right)\)
- D \(\vec E = - {v_0}{B_0}\left( {14\hat j + 7\hat k} \right)\)
Answer & Solution
Correct Answer
(D) \(\vec E = - {v_0}{B_0}\left( {14\hat j + 7\hat k} \right)\)
Step-by-step Solution
Detailed explanation
According to question, as the test charge experiences no net force in that region i.e., sum of electric force \(\left( {{{\text{F}}_{\text{e}}} = {\text{q}}\overrightarrow {\text{E}} } \right)\,\) and magnetic forces…
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