A 1.0 μF capacitor is charged to 50v. The charging battery is disconnected and a 10mH coil is connectd across the condenser, so that L-C oscillations occur. The maximum current in the circuit (R = 0) is
9.25 A
0.5 A
0.75 A
1.0 A
The time constant of C - R circuit is
1/CR
C/R
CR
R/C
Hot wire ammeters are used for measuring
a.c. only
d.c. only
Both a.c. and dc
None of these
An alternating voltage (in volts) given by
V = 200 √2 sin (100 t), is connected to a 1 μF capacitor through an AC ammeter. The reading of the ammeter will be
10 mA
20 mA
40 mA
80 mA
The reactance of a capacitor of capacitance C is X. If both the freqauency and capacitance be doubled, then new reactance will be
X
2X
4X
X/4
In an AC circuit, the rms value of current, irms is related to the peak current, i0 by the relation
irms = √2i0
irms = πi0
irms = i0/π
irms = 1/√2 i0
A 20 V a.c. is applied to a circuit consisting of resistance and a coil of negligible impedance. If the voltage drop across resistance is 12V.Find out the voltage across the coil ?
10 V
8 V
6 V
16 V
An a.c. circuit having an inductor and a resistor in series draws a power of 560 W from a source marked 210 V, 60 Hz. If the power factor of the circuit is 0.8,What will be the impedance of the circuit ?
103 Ω
63 Ω
12 Ω
114 Ω
A coil of inductive reactance 31 Ω has a resistance of 8 Ω. It is placed in series with the condenser of capacitative reactance 25 Ω. The combination is connected to an AC source of 110 V. The power factor of the circuit is
0.56
0.64
0.80
0.33
A L-C circuit is in a state of resonance. If C = 0.1 μF and L = 0.25 H, then neglecting the ohmic resistance of the circuit, find the frequency of oscillations.
1007 Hz
100 Hz
109 Hz
500 Hz
