INSIGHT UPSC QUIZ

Science & Technology General Science
Q.

 With reference to ‘Magnetic Field’, consider the following statements:

1. The magnetic field produced by a current-carrying wire at a given point depends directly on the current passing through it.

2. The magnetic field inside a long straight solenoid-carrying current is zero.

Which of the statement(s) given above is/are correct?

Explanation:

 ANSWER: (A) 

  • Statement 1 is correct.

The magnetic field produced by a current-carrying wire at a given point depends directly on the current passing through it. Therefore, if there is a circular coil having ‘n’ turns, the field produced is ‘n’ times as large as that produced by a single turn. This is because the current in each circular turn has the same direction, and the field due to each turn then just adds up. 

  • Statement 2 is not correct.

A coil of many circular turns of insulated copper wire wrapped closely in the shape of a cylinder is called a solenoid. The pattern of the magnetic field lines around a current-carrying solenoid is similar to a bar magnet. One end of the solenoid behaves as a magnetic north pole, while the other behaves as the south pole. The field lines inside the solenoid are in the form of parallel straight lines. 

This indicates that the magnetic field is the same at all points inside the solenoid. That is, the field is uniform inside the solenoid.

More Questions Selected Just For You. Attempt Now!