question_answer

An aluminium ring B faces an electromagnet A. The current \[I\]through A can be altered. Then which of the following statements is correct?

A)  If \[I\]decreases, A will repel B

B)  Whether \[I\] increases or decreases, B will not experience any force

C)  If \[I\] increases, A will repel B

D)  If \[I\] increases, A will attract B

Correct Answer: C

Solution :

If \[\text{I}\]increases then magnetic field in coil will be increases and \[\text{\vec{B}}\]will acts as shown in ring \[\text{B}\,\text{I}\]will induce in such away that will opposes the increases of \[\text{I}\]in electromagnet. Hence in B direction of \[\text{\vec{B}}\]will be as shown. Hence repel B.