To find the r.m.s value of an alternating current mathematically we need to have ________________?

Related Mcqs:

1. An alternating current is represented by the equation I = I∫sinπt which of the following equation represents an alternating current of frequency and amplitude twice that of the above current ?

   A. I = 2I∫Sin(πt/2)
   B. I = 2I∫Sin(2πt)
   C. I = 2ISinπt
   D. I = I∫sin(2πt)

2. The value of the steady current which when flowing through the same resistor produces heat at the same rate as the mean rate of heat produced by the alternating current is__________________?

   A. Average current
   B. Sinusoidal current
   C. r.m.s current
   D. Net current

3. An alternating current of the r.m.s value of 4.0 A and frequency 50Hz flows in a circuit containing a 10Ω resistor. The peak current is then ?

   A. 20A
   B. 20.66A
   C. 6.66A
   D. 5.66A

4. An alternating current or voltage_____________________?

   A. fluctuates off and on
   B. varies in magnitude alone
   C. changes its direction again and again
   D. changes its magnitude harmonically and reverses its direction of flow after regularly recurring intervals

5. The alternating voltage is an example of_______________?

   A. A digital waveform
   B. An analogue waveform
   C. Discrete waveform
   D. None at all

6. When A.C current passes through a capacitor then the current relationship will be_______________?

   A. The current lead voltage by phase angle is 90 degrees
   B. The voltage leads current by phase angle is 90 degrees
   C. The current lead voltage by phase angle is 45 degrees
   D. The voltage leads current by phase angle is 45 degrees

7. What is the value of the current in a wire of 10cm long at the right angle to a uniform magnetic field of 0.5 Weber/m2 when the force acting on the wire is 5N ?

   A. 1A
   B. 10A
   C. 100A
   D. 1000A

8. An emf of 5 volt is produced by a self inductance, when the current changes at a steady rate from 3 to 2 ampere in 1 millisecond. The value of self inductance is_______?

   A. zero
   B. 5 H
   C. 5000 H
   D. 5 mH

   Submitted by: Tauseef Ali

9. An inductor may store energy in ________________?

   A. Its electric field
   B. Its coils
   C. Its magnetic field
   D. Both electric and magnetic fields

10. A 10Ω electric heater is connected to a 220V 50Hz mains supply. What is the peak value of the potential difference across the heater element ?

    A. 220V
    B. 220/ 2V
    C. 110V
    D. 220 √2V