Question

The use of a radial magnetic field, in which \(\sin\theta = 1\) at all positions, produces a galvanometer scale deflection that is:

Options

• linear and directly proportional to the current

• quadratic in the current

• independent of the current

• inversely proportional to the current

Answer 1

Because \(\sin\theta = 1\) everywhere, the deflecting torque \(\tau = NIAB\) is balanced by the restoring torque \(C\phi\), giving \(\phi \propto I\). This makes the scale linear and uniform.