JEE Mains · Physics · STD 12 - Moving charges and magnetism
- JEE Mains 2022
- Hard
- Numerical
A charge particle is moving in a uniform magnetic field \((2 \hat{i}+3 \hat{j}) T\). If it has an acceleration of \((\alpha \hat{i}-4 \hat{j}) m / s ^{2}\), then the value of \(\alpha\) will be.
Pick an option to check your answer.
Answer & Solution
Correct Answer
(B) \(6\)
Step-by-step Solution
Detailed explanation
As \(\overrightarrow{ F }= q (\overrightarrow{ v } \times \overrightarrow{ B })\)
\(\overrightarrow{ a }=\frac{ q }{ m }(\overrightarrow{ v } \times \overrightarrow{ B })\)
So, \(\overrightarrow{ a }\,and\,\overrightarrow{ B }\) are \(\perp\) to each other
Hence, \(\vec{a} \cdot \vec{B}=0\)
\((\alpha \hat{i}-4 \hat{j}) \cdot(2 \hat{i}+3 \hat{j})=0\)
\(\alpha(2)+(-4)(3)=0\)
\(\alpha=\frac{12}{2} \Rightarrow \alpha=6\)
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