A compass needle is placed near a current - carrying straight wire . State your observation for the following case and give reason for the same in each case :
(1) Direction of electric current in the wire is increased .
(2) Magnitude of electric current in the wire is increased .
(3) Teh compass needle is displaced away from the straight wire .

Explanation

(1) Deflection of the compass needle changes.
Because the direction of the magnetic field due to a current is dependent on the direction of the current and hence the deflection of the compass needle change .
(2) Deflection of the compass needle at a give point increase .
(3) Deflection of the compass needle for a given current decreases.
Because magnetic field strenght is inversely proportional to the distance from the wire .