The work-energy theorem states that the change in kinetic energy of the particle is equal to the work done on the particle:

The work done on the particle is the integral of the force on dx:

So, this corresponds to the change in kinetic energy of the particle.
If there is no current in the wire .....the direction of magnetic field remains unchanged
Answer:
B. Glass
Explanation:
An electrical insulator is a substance that does not conduct electricity.
Glass has tightly bounded electrons, that is why it is an insulator of electricity.
That could be an electromagnet,
and it could also be an solenoid.