Usually, the field coils of D.C. generator are made from
Usually, the field coils of D.C. generator are made from: Silica Copper Graphite Aluminum Correct answer: 2. Copper
MCQs
The approximate thickness of laminations of a D.C. machine is
The approximate thickness of laminations of a D.C. machine is: 0.05 mm 0.5 mm 1 mm 1.5 mm Correct answer: 2. 0.5 mm
Generally the preferred DC Motor for cranes and hoists is
Generally the preferred DC Motor for cranes and hoists is: Cumulatively compound motor Differentially compound motor Series motor Shunt motor Correct answer: 3. Series motor
If all waves have same peak value then which of the following wave will have the smallest RMS value
If all waves have same peak value then which of the following wave will have the smallest RMS value: Square wave Sine wave Half wave rectified sine All have same Correct answer: 3. Half wave rectified sine
If all waves have same peak value then which of the following wave will have the highest RMS value
If all waves have same peak value then which of the following wave will have the highest RMS value: Square wave Triangular wave Sine wave Half wave rectified sine Correct answer: 1. Square wave
Two waves having same frequency have opposite phase when the phase angle between them is
Two waves having same frequency have opposite phase when the phase angle between them is: 0° 90° 135° 180° Correct answer: 4. 180°
The RMS value and mean value is the same in the case of which wave
The RMS value and mean value is the same in the case of which wave: Square wave Triangular wave Sine wave Half wave rectified Correct answer: 1. Square wave
A sine wave has peak value 300 V. Its average value is
A sine wave has peak value 300 V. Its average value is: 122.4 V 191.1 V 282.8 V 352 V Correct answer: 2. 191.1 V Explanation: For sine wave Average value = Peak value * 0.637 = 300 * 0.637 = 191.1 V
In North America, power companies distribute at 120 V, 60 Hz. The voltage 120 refers to
In North America, power companies distribute at 120 V, 60 Hz. The voltage 120 refers to: Average voltage Peak to peak value Peak voltage R.M.S Voltage Correct answer: 4. R.M.S Voltage
AC voltage at service mains in the majority of Asian countries is 230 V, at 50 Hz. The 230 V refers to
AC voltage at service mains in majority of Asian countries is 230 V, at 50 Hz. The 230 V refers to: Average voltage Peak to peak value Peak voltage R.M.S Voltage Correct answer: 4. R.M.S Voltage