The net resistance of a voltmeter should be large to ensure that :
1. | It does not get overheated |
2. | It draws excessive current |
3. | It can measure large potential difference |
4. | It does not appreciably change the potential difference to be measured |
A galvanometer having a resistance of 8 ohms is shunted by a wire of resistance 2 ohms. If the total current is 1 amp, the part of it passing through the shunt will be :
(1) 0.25 amp
(2) 0.8 amp
(3) 0.2 amp
(4) 0.5 amp
A voltmeter of resistance 1000 Ω gives full-scale deflection when a current of 100 mA flow through it. The shunt resistance required across it to enable it to be used as an ammeter reading 1 A at full-scale deflection is :
(1) 10000 Ω
(2) 9000 Ω
(3) 222 Ω
(4) 111 Ω
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 ohm |
2. | Less than 10 ohm |
3. | More than 10 ohm |
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
A galvanometer with a resistance of 36 Ω is changed into an ammeter by using a shunt of 4 Ω. The fraction f0 of total current passing through the galvanometer will be:
1.
2.
3.
4.
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