If an ammeter \(A\) reads \(2\) A and the voltmeter \(V\) reads \(20\) V, what is the value of resistance \(R\)? (Assuming finite resistances of ammeter and voltmeter)
1. | Exactly \(10~\Omega\) |
2. | Less than \(10~\Omega\) |
3. | More than \(10~\Omega\) |
4. | We cannot definitely say |
A galvanometer has a resistance of 25 ohm and a maximum of 0.01 A current can be passed through it. In order to change it into an ammeter of range 10 A, the shunt resistance required is
1. 5/999 ohm
2. 10/999 ohm
3. 20/999 ohm
4. 25/999 ohm
A galvanometer has 30 divisions and a sensitivity 16 It can be converted into a voltmeter to read 3 V by connecting (approximately):
1. Resistance nearly 6 k Ω in series
2. 6 k Ω in parallel
3. 500 Ω in series
4. It cannot be converted
A voltmeter has a range 0-V with a series resistance R. With a series resistance 2R, the range is 0-V'. The correct relation between V and V' is :
1.
2.
3.
4.
If an ammeter is to be used in place of a voltmeter then we must connect with the ammeter a :
1. Low resistance in parallel
2. High resistance in parallel
3. High resistance in series
4. Low resistance in series
1. | \(\dfrac{1}{40}\) | 2. | \(\dfrac{1}{4}\) |
3. | \(\dfrac{1}{140}\) | 4. | \(\dfrac{1}{10}\) |
A galvanometer, having a resistance of 50 Ω gives a full scale deflection for a current of 0.05 A. The length in meter of a resistance wire of area of cross-section 2.97× 10–2 cm2 that can be used to convert the galvanometer into an ammeter which can read a maximum of 5 A current is (Specific resistance of the wire = 5 × 10–7 Ωm)
1. 9
2. 6
3. 3
4. 1.5
An ammeter reads up to 1 ampere. Its internal resistance is 0.81 ohm. To increase the range to 10 A the value of the required shunt is :
1. 0.09 Ω
2. 0.03 Ω
3. 0.3 Ω
4. 0.9 Ω
The current flowing in a coil of resistance \(90~\Omega\) is to be reduced by \(90\%\). What value of resistance should be connected in parallel with it?
1. \(9~\Omega\)
2. \(90~\Omega\)
3. \(1000~\Omega\)
4. \(10~\Omega\)
A galvanometer of \(50~\Omega \) resistance has 25 divisions. A current of 4 × 10–4 A gives a deflection of one division. To convert this galvanometer into a voltmeter having a range of 25 V, it should be connected with a resistance of:
1. 2500 Ω as a shunt
2. 2450 Ω as a shunt
3. 2550 Ω in series
4. 2450 Ω in series