The effective value of an alternating current is 5 A. The current passes through 24 Ω resistor. The maximum potential difference across the resistor is
10 V
170 V
17 V
1700 V
An AC supply gives 30 Vrms which passes through a 10 Ω resistance. The power dissipated in it is
90 √2 W
90 W
45√2 W
45 W
An alternating voltage V = 200√2 sin (100t) is connected to a 1μF capacitor through an AC ammeter. The reading of the ammeter shall be
10 mA
20 mA
40 mA
80 mA
In an experiment, 200 V AC is applied at the ends of an LCR circuit. The circuit consists of an inductive reactance (XL) = 50 Ω, capacitive reactance (XC) = 50 Ω and ohmic resistance (R) = 10 Ω. The impedance of the circuit is
10 Ω
20 Ω
30 Ω
40 Ω
A transformer is used to light a 100 W and 110 V lamp from a 220 V mains. If the main current is 0.5 A, the efficiency of the transformer is approximately
30%
50%
90%
10 %
Hot wire ammeters are used for measuring
a.c. only
d.c. only
Both a.c. and dc
None of these
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
A wire of resistance R is connected in series with an inductor of reactance ωL. Then quality factor of RL circuit is
An alternating voltage E = 220√2 sin 100 t is connected to 1μF capacitor through an a.c. ammeter. The reading of the ammeter shall be
22 mA
A hot wire ammeter reads 10 A in an a.c. circuit. The peak value of current is
10/√2 A
20/π A
5 π A
10 √2 A
