# An ac voltmeter using full-wave rectification and having a sinusoidal input has an ac sensitivity equal to

1.  1.414 times de sensitivity

2.  dc sensitivity

3.  0.90 times de sensitivity

4.  0.707 times dc sensitivity

4

0.90 times de sensitivity

Explanation :
No Explanation available for this question

# A 1 cm piezoelectric transducer having a g-coefficient of 58 V/kg/m2 is subjected to a constant pressure of 10 kg/m2 for about 15 minutes. The piezo voltage developed by the transducer will be

1.  116 mV

2.  58 mV

3.  29 mV

4.  0 mV

4

58 mV

Explanation :
No Explanation available for this question

# In an oscilloscope, two Lissajous figure (X) and (Y) are observed. This indicates that ratio of vertical input signal frequency to that of horizontal input frequency are

1.  5/3 for X and 3/2 for V

2.  3/2 for X and 5/3 for Y

3.  5/3 for X and 5/3 for Y

4.  3/2 for X and 3/2 for Y

4

3/2 for X and 3/2 for Y

Explanation :
No Explanation available for this question

# A C.R.O. is operated with X and Y settings of 0.5 mV/cm and 100 mV/cm. The screen of the C.R.O. is 10 cm x 8 cm (X and Y). A sine wave of frequency 200 Hz and r.m.s. amplitude of 300 mV is applied to the Y-input. The screen will show

1.  one cycle of the undistorted sine wave

2.  two cycles of the undistorted sine wave

3.  one cycle of the sine wave with clipped amplitude

4.  two cycles of the sine wave with clipped amplitude

4

one cycle of the undistorted sine wave

Explanation :
No Explanation available for this question

# A Wien-bridge is used to measure the frequency of the input signal. However the input signal has 10% third harmonic distortion. Specifically the signal is 2 sin 400πl+0.2 sin 1200πt (with t in sec). With this input the balance will

1.  lead to a null indication and setting will correspond to a frequency of 200 Hz

2.  lead to a null indication and setting, will correspond to 260 Hz

3.  lead to a null indication and setting will Correspond to 400Hz

4.  not lead to null indication

4

Explanation :
No Explanation available for this question

# Three d.c. voltmeters are connected in series across a 120 V d.c. supply. The voltmeters are specified as follows : Voltmeter. A : 100V,5mA. Voltmeter B: 100 V, 250 ohms/V Voltmeter C.: 10 mA, 15,000 ohms The voltage read by the meters A,B and C are, respectively

1.  40,50 and 30 V

2.  40,40 and 40 V

3.  60,30 and 30 V

4.  30,60 and 300 V

4

40,50 and 30 V

Explanation :
No Explanation available for this question

# A 0 to 200V voltmeter has a guaranteed accuracy of 1% of full scale reading.The Voltage measured by this instrument is 50 V. What is the limiting error

1.  4%

2.  2%

3.  1%

4.  0.25%

4

4\%

Explanation :
No Explanation available for this question

# Which one of the following methods decreases the error due to connections in a dynamometer type wattmeter

1.  Using bifilar compensating winding in place of current coil

2.  Using non-inductive pressure coil circuit

3.  Using a capacitor across a part Of high resistance of pressure -coil circuit

4.  Using a swamping resistance

4

Using bifilar compensating winding in place of current coil

Explanation :
No Explanation available for this question

# An electronic voltmeter is more reliable as compared to multimeter for measuring voltage across low impedance because

1.  its sensitivity is high

2.  it offers high input impedance

3.  it does not alter the measured voltage

4.  its sensitivity, and input impedance are high and do not alter the measured value

4

its sensitivity, and input impedance are high and do not alter the measured value

Explanation :
No Explanation available for this question

# Which one of the following decides the time of response of an indicating instrument

1.  Deflecting system

2.  Controlling system

3.  Damping system

4.  Pivot and Jewel bearing

4