Question

In a moving coil galvanometer the deflection $( \phi )$ on the scale by a pointer attached to the spring is

• A. $\left( \frac { \mathrm { NA } } { \mathrm { kB } } \right) \mathrm { I }$
• B. $\left( \frac { \mathrm { N } } { \mathrm { kAB } } \right) \mathrm { I }$
• C.
• D. $\left( \frac { \mathrm { NAB } } { \mathrm { kI } } \right)$

Answer 1

Answer: (C)

Answer 2

Since magnetic torque on the coil this torque is balanced by counter torque

$\therefore \mathrm { k } \phi = \mathrm { NIAB }$ or $\phi = \left( \frac { \mathrm { NAB } } { \mathrm { k } } \right) \mathrm { I }$

Where k is torsional constant It is a scalar quantity having dimension of torque or energy i.e. $\left[ \mathrm { ML } ^ { 2 } \mathrm {~T} ^ { - 2 } \right]$