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 ?

Related Mcqs:

1. 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

2. An inductive coil has a resistance of 100Ω. When an AC signal of frequency 1000Hz is fed to the coil the applied voltage leads the current by 45Ω. What is the inductance of the coil ?

   A. 10mH
   B. 12mH
   C. 16mH
   D. 20mH

3. A wire of resistance R is coiled inductively so that its inductance is L. The impedance of the coil at a frequency of f is_______________?

   A. (R+2πfL)
   B. R+1/2πfL
   C. (R2+f2L2)
   D. (R2+4π2f2L2)

4. Coil of a galvanometer is suspended in a radial magnetic field so that the deflecting torque on the coil is always___________________?

   A. BINA cosa
   B. BINA sina
   C. BINA tana
   D. BINA

5. If the plane of the rectangular coil is parallel to the magnetic field (i.e radial magnetic field) the torque on the coil is_____________________?

   A. τ = NIAB cosφ
   B. τ = NIAB sinφ
   C. τ = NIAB tanφ
   D. τ = NIAB

6. 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

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

   A. Zero
   B. Maximum
   C. Minimum
   D. Optimum

   Submitted by: Raza Baloch

8. A moving coil galvanometer of resistance 100? gives half scale deflection for a current of 20mA. What will be the potential difference across it ?

   A. 4 volt
   B. 5 volt
   C. 2 volt
   D. 0.4 volt

9. When a pure inductor of inductance L and a pure capacitor of capacitance C are connected in parallel to a sinusoidal potential difference V the potential difference across both L & C will be_______________?

   A. Same
   B. Different
   C. At L will be more than at C
   D. At L will be less than at C

10. 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)