# Measuring Instruments Objective Type Questions

### 40. The watt-hour meter is ………. instrument.

(i) an integrating
(ii) an indicating
(iii) a recording
(iv) a transfer

### 41. Indicating instruments are assumed to be most accurate ……… part of scale.

(i) at beginnig
(ii) at finishing
(iii) at half of full
(iv) none of the above

(i) 50 mA
(ii) 100 µA
(iii) 50 µA
(iv) 1 µ A

### 43. On a simple ohmmeter, the 0 Ω mark is ……… of the scale.

(i) far left
(ii) in the middle
(ii) far right
(iv) none of the above

### 44. If a wattmeter connected in circuit gives down scale reading, then we normally change connections of

(i) current coil
(ii) potential coil
(iii) both current and potential coils
(iv) none of above

### 45. A permanent magnet moving coil ammeter is connected in 50 Hz a.c. circuit in which 5A current is flowing. The meter will read

(i) 0 A
(ii) 5 A
(iii) 2.5 A
(iv) none of above

### 46. In the above question, if the meter remains connected in the circuit for sometime,

(i) meter pointer gives full-scale deflection
(ii) meter pointer starts oscillating
(iii) meter coil is burnt
(iv) none of above

### 47. If in the above question, the frequency of a.c. 0.1 Hz, the pointer will

(i) rise from zero and then falls back
(iv) none of above

### 48. On a simple ohmmeter, the infinity Ω mark is …….. of the scale.

(i) far left
(iii) in the middle
(ii) far right
(iv) none of above

### 49. The instrument used in an ohmmeter is generally

(i) moving-iron type
(ii) hot-wire type
(iii) permanent magnetic moving coil type
(iv) Dynamometer type

### 50. When the terminals of a series ohmmeter are open-circuited, the pointer reads

(i) zero
(ii) infinity
(iii) a high resistance
(iv) none of above

### 51. Out of the following, the most accurate measurement of unknown resistance will be by

(i) potentiometer
(ii) ohmmeter
(iii) voltmeter and ammeter
(iv) Wheatstone bridge

(i) 2.5 k Ω
(ii) 0.4 k Ω
(iii) 10 k Ω
(iv) 1 M Ω

### 53. Voltmeter-ammeter method of measuring the value of resistance is used to measure if its value is

(i) very low
(ii) very high and moderate
(iii) cannot say
(iv) none of above

### 54. In a dynamometer wattmeter, the moving coil is the

(i) current coil
(ii) potential coil
(iii) current coil or potential coil
(iv) none of the above

### 55. Fig. 1 shows an ammeter, a voltmeter and a wattmeter connected in the circuit. The wattmeter will read

(i) upscale
(ii) down scale
(iii) data insufficient
(iv) none of above

### 56. In the circuit shown in Fig. 1, the wattmeter reading will be

(i) equal to actual load power
(ii) less than actual load power
(iii) more than actual load power
(iv) none of above

### 57. In Fig. 1, the ammeter reading will be

(i) equal to the load current
(ii) more than the load current
(iii) less than the load current
(iv) cannot be predicted

(i) 125.8 W
(ii) 180.7 W
(iii) 224.6 W
(iv) 352.8 W

(i) 6.25 %
(ii) 4.85 %
(iii) 11.34 %
(iv) 7.86 %

### 60. Induction wattmeter can measure

(i) a.c. power only
(ii) d.c. power only
(iii) both a.c. and d.c. power
(iv) none of above

### 61. To measure a.c. as well as d.c. power, we use

(i) induction wattmeter
(ii) dynamometer wattmeter
(iii) sometimes induction and sometimes dynamometer wattmeter
(iv) none of above

### 62. In a single phase energy meter, braking torque is provided by

(i) permanent magnet
(ii) air friction
(iii) fluid friction
(iv) none of above

### 63. The full-scale deflection current of a permanent magnet moving-coil (PMMC) meter is 1 mA and the coil resistance is 50 Ω. The least voltage that can be measured with this meter is

(i) 50 mV
(ii) 25 mV
(iii) 100 mV
(iv) none of above

### 64. If the full-scale current of a meter is 50 µA, then its sensitivity is

(i) 1000 Ω/V
(ii) 20,000 Ω/V
(iii) 10,000 Ω/V
(iv) data insufficient

(i) 0.5 mA
(ii) 2 mA
(iii) 3.5 mA
(iv) 1 mA

(i) 2 Ω
(ii)6 Ω
(iii) 4 Ω
(iv) 1 Ω

### 67. Which of the following is likely to have the largest resistance ?

(i) moving coil galvanometer
(ii) voltmeter of range 10 V
(iii) ammeter of range 1 A
(iv) a copper wire of length 1m and diameter 3 mm

(i) G/49
(ii) G/50
(iii) 49 G
(iv) 50 G

(i) S/(S + G)
(ii) G/(G + S)
(iii) SG/(G + S)
(iv) G2/(G + S)