Question

1. Two parallel current carrying wires will attract each other if:

(a) Current run through the wires in opposite directions.

(b) Current run through the wires in the same direction.

(c) The wires cannot attract each other.

2. How could the force exerted on a straight wire that carries current due to Earth’s magnetic field be minimized?

(a) Align the wire perpendicular to Earth’s magnetic field. (

b) Align the wire parallel to Earth’s magnetic field.

(c) Align the at a 45 degree angle with Earth’s magnetic field.

(d) The force cannot be minimized.

3. What is the Hall effect?

(a) The creation of a potential difference across the diameter of a current carrying wire when placed in a magnetic field.

(b) The creation of a potential difference across the diameter of a current carrying wire when placed in an electric field.

(c) The force exerted on a current carrying wire when placed in a magnetic field.

(d) The force exerted on a current carrying wire when placed in an electric field.

Answer 1

Solution:

1. (b)

Here,

There are two wires, with their current mving towards us from a far place. The wire on the left generates an upward magnetic field at where the wire on the right is. Using Fleming's left hand rule, we find that the electromagnetic force acting on the wire on the right is directed towards left and the wire on the left is pushed towards the right by another electromagnetic force. This makes it look like an attraction.

Whereas,

When the currents move in opposite directions, the eletromagnetic force causes them to repel each other in the similar way.

2. (b)

Due to earth's magnetic field as we know:

Whenever a current-carrying conductor is running in any direction that is "not"perfectly parallel to the earth's

magnetic field, it'll be pushed by the lorentz force in a direction perpendicular to both the current and the magnetic

field.

3. (a)

This is the simply the definition of hall effect discovered by Edwin Hall in 1879.