At resonance the value of the power factor in an L-C-R series circuit is
A. Zero
B. 2
C. 1
D. Not definite
At resonance the value of the power factor in an L-C-R series circuit is Read More »
Physics
A choke is used as a resistance in
A. DC circuit
B. AC circuits
C. Both AC and DC circuit
D. Full wave rectifier circuit
A choke is used as a resistance in Read More »
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
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
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
Ammeter connected in an AC circuit measures
A. The exact value of the current
B. RMS value of the current
C. The net value of the current
D. The peak value of the current
Ammeter connected in an AC circuit measures Read More »
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+2Ï€fL)
B. R+1/2Ï€fL
C. (R2+f2L2)
D. (R2+4Ï€2f2L2)
If a glass plate is inserted in between the plate of a capacitor in series with a lighted bulb the brightness of the bulb
A. Remains same
B. Brightness increases
C. Brightness decreases
D. No light