Two moving coil galvanometers and are identical except for the following features: Two moving coil…
Two moving coil galvanometers $G_{1}$ and $G_{2}$ are identical except for the following features:
(a)[2.0]
Two moving coil galvanometers $G_{1}$ and $G_{2}$ are identical except for the following features:
Perform calculations to determine which galvanometer has greater current sensitivity.
| Features | $G_{1}$ | $G_{2}$ |
|---|---|---|
| Number of turns | 50 | 60 |
| Area of the coil | $30\text{ cm}^{2}$ | $40\text{ cm}^{2}$ |
| Resistance of the coil | $5\,\Omega$ | $6\,\Omega$ |
(b)[1.0]
In a moving coil galvanometer, how is magnetic field made radial?
Answer
Answer (a)
AIWritten by AI - it can contain mistakes.
Current sensitivity of a moving coil galvanometer is given by:
$I_{s} = \frac{\theta}{I} = \frac{NAB}{k}$
Since both galvanometers are identical in other respects, $B$ and $k$ are the same for both. Thus, $I_{s} \propto NA$.
For galvanometer $G_{1}$:
$N_{1} A_{1} = 50 \times 30\text{ cm}^{2} = 1500\text{ turns}\cdot\text{cm}^{2}$
For galvanometer $G_{2}$:
$N_{2} A_{2} = 60 \times 40\text{ cm}^{2} = 2400\text{ turns}\cdot\text{cm}^{2}$
Since $N_{2}A_{2} > N_{1}A_{1}$, galvanometer $G_{2}$ has greater current sensitivity.
Final answer: G_2
Final answer: G_2
Answer (b)
AIWritten by AI - it can contain mistakes.
The magnetic field is made radial by using concave-shaped (cylindrical) magnetic pole pieces and placing a cylindrical soft iron core symmetrically between them.
From ISC 2026 Physics Paper 1, question 11(ii).