JEE Mains · Physics · STD 12 - 4. Moving charges and magnetism
A rigid wire consists of a semicircular portion of radius \(R\) and two straight sections. The wire is partially immerged in a perpendicular magnetic field \(B=B_0\ {j}\) as shown in figure. The magnetic force on the wire if it has a current \(i\) is _______.
- A \(-\mathrm{iBR} \hat{\mathrm{j}}\)
- B \(2 \mathrm{iBR} \hat{\mathrm{j}}\)
- C \(i B R \hat{j}\)
- D \(-2 i B R \hat{j}\)
Answer & Solution
Correct Answer
(D) \(-2 i B R \hat{j}\)
Step-by-step Solution
Detailed explanation
Note : Direction of magnetic field is in \(+\hat{k}\) \(\vec{F}=i \vec{\ell} \times \vec{B}\) \(\ell=2 \mathrm{R}\) \(\vec{F}=-2 i R B \hat{j}\)
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