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

Question

In a moving coil galvanometer the deflection (φ) on the scale by a pointer attached to the spring is (A) ((NA/KB))I (B) ((N/KAB))I (C) ((NAB/K))I (D) ((NAB/KI))I

Tardigrade Admin · Accepted Answer

Since magnetic torque on the coil, τ =NIAB This torque is balanced by counter torque ∴ kφ =NIAB or (φ=(NAB/K))I where k is torsional constant. It is a scalar quantity having dimension of torque or energy i.e. [ML2T-2]

Q. In a moving coil galvanometer the deflection $(ϕ)$ on the scale by a pointer attached to the spring is

$(\frac{N A}{K B}) I$

$(\frac{N}{K A B}) I$

$(\frac{N A B}{K}) I$

$(\frac{N A B}{K I}) I$

Since magnetic torque on the coil, $τ = N I A B$
This torque is balanced by counter torque
$∴ k ϕ = N I A B$ or $(ϕ = \frac{N A B}{K}) I$
where $k$ is torsional constant. It is a scalar quantity having dimension of torque or energy i.e. $[M L^{2} T^{- 2}]$

Q. In a moving coil galvanometer the deflection (ϕ) on the scale by a pointer attached to the spring is

(KBNA​)I

(KABN​)I

(KNAB​)I

(KINAB​)I