suprize quiz 2 -mech

1 The power factor of a D.C. circuit is always ___

• less than unity

• unity

• greater than unity

• zero

The form factor is the ratio of ___

• peak value of r.m.s value

• r.m.s value to average value

• average value to r.m.s value

• average value to peak value

According to Kirchhoff’s voltage law, the algebraic sum of all IR drops and e.m.f. in any closed loop of a

network is always ___

 

• negative

• positive

• determined by battery e.m.f

• zero

The peak value of a sine wave is 200 V. Its average value is —– R

a. 127.4 V b. 141.4 V

c. 282.8 V d. 200V

• 127.4 v

• 282.8v

• 141.4v

• 200v

For a frequency of 200 Hz, the time period will be —–

• 0.05s

• 0.005s

• 0.0005s

• 0.5s

The input of an A.C. circuit having power factor of 0.8 lagging is 40 kVA.The power drawn by the circuit

is —–

• 12 kw

• 22kw

• 32kw

• 64kw

In a pure inductive circuit —–

• the current is in phase with the voltage

• the current lags behind the voltage by 90°

• the current lags behind the voltage by 90°

• the current can lead or lag by 90°

Power factor of electric bulb is ___

• zero

• lagging

• leading

• unity

In a certain three-wire Y-connected generator, the phase voltages are 2 kV. The magnitudes of the line

voltages are _

• 2000 v

• 6000 v

• 666 v

• 3464 v

In a three-phase system, the voltages are separated by

• 45°

• 90°

• 120°

• 180°