Question

A wire is sliding as shown in the figure. The angle between acceleration and velocity of the wire at the instant shown is :

• A. ${30}^{\circ }$
• B. ${40}^{\circ }$
• C. ${120}^{\circ }$
• D. ${90}^{\circ }$

Answer 1

The correct option is C ${120}^{\circ }$

According to the right-hand rule, end $\text{A}$ will be at higher potential and end $\text{B}$ will be at lower potential.

Therefore, the current will flow in the wire from point $\text{B}$ to $\text{A}$ as shown in the figure below.


Due to this current, magnetic force will act on the wire.

Using the right-hand thumb rule we can say that the direction of the magnetic force is perpendicular to the length of wire as shown in the figure.


We know that the acceleration is directed along the direction of force.

Therefore, we can say that the angle between the acceleration and velocity of the wire is,

$\theta ={90}^{\circ }+{30}^{\circ }={120}^{\circ }$

Hence, $\left(C\right)$ is the correct answer.