Q. No.A galvanometer having a coil resistance of \(100~\Omega\) gives a full-scale deflection when a current of \(1~\text{mA}\) is passed through it. The value of the resistance which can convert this galvanometer into an ammeter giving a full-scale deflection for a current of \(10~\text{A}\), is:
1. \(0.01~\Omega\)
2. \(2~\Omega\)
3. \(0.1~\Omega\)
4. \(3~\Omega\)
1. \(1.25 Ć 10^{ā2}~\Omega\)
2. \(2.5 Ć 10^{ā3}~\Omega\)
3. \(2.5 Ć 10^{ā2}~\Omega\)
4. \(1.25 Ć 10^{ā3}~\Omega\)
1. \(40~\text{V}\)
2. \(10~\text{V}\)
3. \(15~\text{V}\)
4. \(20~\text{V}\)
A galvanometer has a resistance of \(100~\Omega,\) a full-scale deflection of \(50\) divisions, and a current sensitivity of \(20~\mu\text{A/division}.\) It is to be converted into a voltmeter with three ranges: \(0\text-2~\text{V},~0\text{-}10~\text{V}~\text{and}~0\text{-}20~\text{V}.\) Which of the following circuits is appropriate to achieve these voltage ranges?
| 1. |  |
| 2. |  |
| 3. |  |
| 4. |  |
A moving coil galvanometer, having a resistance \(G\), produces full scale deflection when a current \(I_g\) flows through it. This galvanometer can be converted into (i) an ammeter of range \(0\) to \(I_0\) (\(I_0>I_g\)) by connecting a shunt resistance \(R_A\) to it and (ii) into a voltmeter of range 0 to \(V (V=GI_0)\) by connecting a series resistance \(R_V\) to it. Then,
| 1. | \(R_AR_V=G^2 \text{ and } \frac{R_A}{R_V}=\frac{I_g}{I_0-I_g}\) |
| 2. | \(R_AR_V=G^2\left(\frac{I_g}{I_0-I_g}\right) \text{ and } \frac{R_A}{R_V}=\left(\frac{I_0-I_g}{I_g}\right)^2\) |
| 3. | \(R_AR_V=G^2\left(\frac{I_g}{I_0-I_g}\right) \text{ and } \frac{R_A}{R_V}=\left(\frac{I_g}{I_0-I_g}\right)^2\) |
| 4. | \(R_AR_V=G^2 \text{ and } \frac{R_A}{R_V}=\left(\frac{I_g}{I_0-I_g}\right)^2\) |
Which of the following will NOT be observed when a multimeter (operating in resistance measuring mode) probes connected across a component, are just reversed?
| 1. | Multimeter shows an equal deflection in both cases i.e. before and after reversing the probes if the chosen component is resistor. |
| 2. | Multimeter shows NO deflection in both cases i.e. before and after reversing the probes if the chosen component is metal wire. |
| 3. | Multimeter shows a deflection, accompanied by a splash of light out of connected component in one direction and NO deflection on reversing the probes if the chosen component is LED. |
| 4. | Multimeter shows NO deflection in both cases i.e. before and after reversing the probes if the chosen component is capacitor. |
A galvanometer of resistance \(G\) is converted into a voltmeter of range \(0\text-1\) V by connecting a resistance \(R_1\) in series with it. The additional resistance that should be connected in series with \(R_1\) to increase the range of the voltmeter to \(0\text-2\) V will be:
1. \(R_1\)
2. \(R_1+G\)
3. \(R_1-G\)
4. \(G\)
\( R_1=5~ \Omega, N_1=15, A_1=3.6 \times 10^{-3} ~\text{m}^2, B_1=0.25 ~\text{T} \)
\(R_2=7 ~\Omega, N_2=21, A_2=1.8 \times 10^{-3} ~\text{m}^2, B_2=0.50 ~\text{T} \)
Assuming that torsional constant of the springs are same for both coils, what will be the ratio of voltage sensitivity of \(M_1\) and \(M_2\)?
1. \(1:3\)
2. \(1:2\)
3. \(1:4\)
4. \(1:1\)
In laboratory experiments, a galvanometer is often used to detect the null point. The figure of merit of a galvanometer is a measure of its sensitivity, defined as the current required to produce a unit deflection (usually \(1\) division on the scale). If a galvanometer produces a deflection of \(2^\circ,\) when a current of \(6~\text{mA}\) is passed through it, what is its figure of merit?
1. \( 3 \times 10^{-3} ~\text{A/div}\)
2. \( 333^{\circ} ~\text{A/div}\)
3. \( 6 \times 10^{-3} ~\text{A/div}\)
4. \( 666^{\circ} ~\text{A/div}\)
1. \(149\)
2. \(298\)
3. \(596\)
4. \(447\)
Ā© 2026 GoodEd Technologies Pvt. Ltd.