Here N = 175 , A = 10 − 4 m 2 , I = 10 − 3 A N = 175,A = 10^{- 4}{\text{\ }m}^{2},I = 10^{- 3}\text{\ }A , θ = 1 ∘ , C = 10 − 6 N - m r a d − 1 \theta = 1^{\circ},C = 10^{- 6}\text{\ }N\text{-}m{rad}^{- 1} To find: The value of magnetic field B B for which the coil deflects by angle θ = 1 ∘ = π 180 r a d , \theta = 1^{\circ} = \frac{\pi}{180}rad, for a current of i = 1 m A i = 1\text{\ }mA .Torque on the coil due to magnetic field: τ = N I B A \tau = NIBA Restoring torque on the coil due to torsion band: τ = C θ \tau = C\theta T h u s N I B A = C θ Thus\ NIBA = C\theta B = C θ N I A B = \frac{C\theta}{NIA} = 10 − 6 × π 180 175 × 1 × 10 − 3 × 1 × 10 − 4 ≈ 10 − 3 T = \frac{10^{- 6} \times \frac{\pi}{180}}{175 \times 1 \times 10^{- 3} \times 1 \times 10^{- 4}} \approx 10^{- 3}\text{\ }T

A moving coil galvanometer has a coil with 175 turns and area 1 cm2. It uses a torsion band of torsion constant 10-6 N-m/rad. The coil is placed in a magnetic field B parallel to its plane. The coil deflects by 1° for a current of 1 mA. The value of B (in Tesla) is approximately

Question 1:

A moving coil galvanometer has a coil with 175 turns and area 1 cm². It uses a torsion band of torsion constant 10^-6 N-m/rad. The coil is placed in a magnetic field B parallel to its plane. The coil deflects by 1° for a current of 1 mA. The value of B (in Tesla) is approximately

$10^{- 3}$

$10^{- 1}$

$10^{- 4}$

$10^{- 2}$

Answer:

Solution:

Here $N = 175,A = 10^{- 4}{\text{\ }m}^{2},I = 10^{- 3}\text{\ }A$ ,

$\theta = 1^{\circ},C = 10^{- 6}\text{\ }N\text{-}m{rad}^{- 1}$

To find: The value of magnetic field $B$ for which the coil deflects by angle

$\theta = 1^{\circ} = \frac{\pi}{180}rad,$

for a current of $i = 1\text{\ }mA$ .

Torque on the coil due to magnetic field: $\tau = NIBA$

Restoring torque on the coil due to torsion band: $\tau = C\theta$

$Thus\ NIBA = C\theta$

$B = \frac{C\theta}{NIA}$

$= \frac{10^{- 6} \times \frac{\pi}{180}}{175 \times 1 \times 10^{- 3} \times 1 \times 10^{- 4}} \approx 10^{- 3}\text{\ }T$

Prev Exam(s):

JEE MAIN

- 2019

, 9 Apr Shift-02

Chapter:

MAGNETIC EFFECTS OF CURRENT (MEC)

Question Level:

Tags:

MAGNETIC EFFECTS OF CURRENT (MEC)
PHYSICS

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