JEE Mains · Physics · STD 12 - Moving charges and magnetism
- JEE Mains 2023
- Medium
- MCQ
A massless square loop, of wire of resistance \(10\,\Omega\). supporting a mass of \(1\,g\). hangs vertically with one of its sides in a uniform magnetic field of \(10^3\, G\), directed outwards in the shaded region. A dc voltage \(V\) is applied to the loop. For what value of V. the magnetic force will exactly balance the weight of the supporting mass of \(1\,g\) ? (If sides of the loop \(=10\,cm , g =10\,ms ^{-2}\) )
Pick an option to check your answer.
Answer & Solution
Correct Answer
(D) \(10\,V\)
Step-by-step Solution
Detailed explanation
\(F _{ m }= mg\)
\(\therefore \quad ILB = mg\)
\(\therefore \quad\left(\frac{ V }{ R }\right) LB = mg\)
\(\therefore \quad V =\frac{ mgR }{ LB }\)
\(=\frac{\left(1 \times 10^{-3}\,kg \right)\left(10\,m / s ^2\right)(10 \Omega)}{(0.1\,m )\left(10^3 \times 10^{-4}\,T \right)}=10\,V\)
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