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
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
Hot wire ammeters are used for measuring
a.c. only
d.c. only
Both a.c. and dc
None of these
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
The primary and secondary coils of a transformer have 50 and 1500 turns respectively. If the magnetic flux Φ linked with the primary coil is given by Φ = Φ0 + 4t, where Φ is in weber, t is time in second and Φ0 is a constant, the output voltage across the secondary coil is
90 V
120 V
220 V
30 V
A wire of resistance R is connected in series with an inductor of reactance ωL. Then quality factor of RL circuit is
In an a.c. circuit, the current is i = 5 sin (100t -π/2) amp and the a.c. voltage is v = 200 sin (100 t) volts. Then power consumption is
200 W
0 W
40 W
1000 W
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
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
10 mA
40 mA
80 mA
An a.c. circuit having an inductor and a resistor in series, draws a power of 560 W from an a.c. source marked 210 V, 60 Hz. If power factor of the circuit is 0.8, then impedance of the circuit is
103 Ω
63 Ω
12 Ω
114 Ω
