The strength of the induced potential difference depends on the relative speed between the coil and the magnet.

$(a)$ What is meant by a 'magnetic field'?
$(b)$ How is the direction of magnetic field at a point determined?
$(c)$ Describe an activity to demonstrate the direction of the magnetic field generated around a current-carrying conductor.
$(d)$ What is the direction of the magnetic field at the centre of a current-carrying circular loop?

The diagram below shows a coil connected to a centre zero galvanometer $G$. The galvanometer shows a deflection to the right when the $N$ pole of a powerful magnet is moved to the right as shown.
$(i)$ Explain why the deflection occurs in the galvanometer.
$(ii)$ Does the direction of current in the coil appear clockwise or anticlockwise when viewed from end $A$?
$(iii)$ State the observation in $G$ when the coil is moved away from $N$.
$(iv)$ State the observation in $G$ when,both coil and the magnet,are moved to the right at the same speed.

Draw magnetic field lines produced around a current-carrying straight conductor passing through a cardboard. How will the strength of the magnetic field change when the point where the magnetic field is to be determined is moved away from the straight wire carrying a constant current? Justify your answer.

What is the shape of magnetic field lines around a straight current-carrying conductor?

What are the factors on which the magnetic field due to a current carrying solenoid depends?