Question

At equilibrium, the deflecting and restoring torques acting on the coil of a moving coil galvanometer satisfy the condition:

Options

• \[C\phi^2 = NIAB\]

• \[NIAB\phi = C\]

• \[NIAB = \frac{C}{\phi}\]

• \[NIAB = C\phi\]

Answer 1

At equilibrium, the deflecting couple \(NIAB\) (with the radial field making \(\sin 90° = 1\)) equals the restoring couple \(C\phi\) of the phosphor-bronze spring of torsional constant \(C\). This balance fixes the steady deflection.