The back emf of a motor which is just started is_________?

Related Mcqs:

1. What is the self-inductance of a coil in which an induced emf of 2V is set up when the current changes at the rate of 4 As-1 ?

   A. 0.5 mH
   B. 0.5H
   C. 2.0H
   D. 8.0H

2. 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

3. The most fundamental of all sciences which provides basic principles and fundamental laws to other branches of science is_________?

   A. biology
   B. physics
   C. information technology
   D. chemistry

4. Atom is the smallest particall which is_________?

   A. Indivisible 
   B. Divisible
   C. Both
   D. Non of these

   Submitted by: Kamran khan

5. Gravitation force of moon is_________?

   A. 7.2 m/s²
   B. 1.62 m/s²
   C. 9.8 m/s²
   D. 3.75 m/s²

   Submitted by: Adeeba Bashir

6. A cube of side 5 cm has a charge of 6 C. The surface density of charge is_________?

   A. 100 C m^–2
   B. 200 C m^–2
   C. 300 C m^–2
   D. 400 C m^–2

   Submitted by: Tauseef Ali

7. The first overtone of a stretched string of given length is 320 Hz. The first harmonic is_________?

   A. 320 Hz
   B. 640 Hz
   C. 160 Hz
   D. 480 Hz

   Submitted by: Tauseef Ali

8. CGS unit of Force is_________?

   A. Newton
   B. Erg
   C. Dyne
   D. Joule

   Submitted by: Kashif Raza Tunio

9. The shaft of a motor rotates at a constant angular speed of 360rev/min. Angle turned through in 1 sec in radian is________________?

   A. π
   B. 3π
   C. 6π
   D. 12π

10. What is wavelength of visible spectrum?

    A. 8500 – 9800 angstrom
    B. 7800 – 8000 angstrom
    C. 3900 – 7600 angstrom
    D. 1300 – 3000 angstrom

    Submitted by: Engr Allah Wadhayo