Question

A conducting loop carrying a current I is placed in a uniform magnetic field pointing into the plane as shown in Fig. The loop will have tendency to :

• A. Contract
• B. Expand
• C. Move towards positive x-axis
• D. Move towards negative x-axis

Answer 1

The correct option is B Expand

$\overrightarrow{dF}=i(\overrightarrow{dl}\times \overrightarrow{B})$
If we take any two small elements diagonally opposite, both will experience force outward. Thus, the conducting loop will be pulled outward at each point.
Hence, the loop will have a tendency to expand.