Magnetic Field Due to a Current Carrying Straight Conductor

A magnetic compass needle is placed in the plane of paper near point A as shown in Figure. In which plane should a straight current carrying conductor be placed so that it passes through A and there is no change in the deflection of the compass? Under what condition is the deflection maximum and why?

Draw a diagram showing the directions of three magnetic field lines due to a straight wire carrying current. Also show the direction of current in the wire.

In the diagram XY is a straight conductor carrying current in the direction marked by the arrow. The conductor is held vertical by passing it through a horizontal cardboard sheet.

Draw three magnetic lines of force on the board and mark the direction of magnetic field in your diagram. State two factors on which magnitude of magnetic field at a point, depends.

How is the magnetic field due to a straight current carrying wire affected if current in wire is decreased?

How is the magnetic field due to a straight current carrying wire affected if current in wire is reversed?

Magnetic lines of force inside current carrying solenoid are ____________.

• Assertion: A compass needle is placed near a current-carrying wire. The deflection of the compass needle decreases when the magnitude of the current in the wire is increased.
• Reason: The strength of a magnetic field at a point near the conductor increases by increasing the current.

These consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:

Assertion: On freely suspending a current – carrying solenoid, it comes to rest in Geographical N-S direction.

Reason: One end of current carrying straight solenoid behaves as a North pole and the other end as a South pole, just like a bar magnet.