CBSE
In a circuit, L, C and R are connected in series with an alternating voltage source of frequency f. The current leads the voltage by 45°. The value of C is
220 V, 50 Hz, AC source is connected to an inductance of 0.2 Hand a resistance of 20 Ω in series. Whatis the current in the circuit?
3.33 A
33.3 A
5 A
10 A
Real power consumption in a circuit is least when it contains.
high R, low L
high R, high L
low R, high L
high R, low C
In an L-C-R circuit inductance is changed from L to L/2.To keep the same resonance frequency, C should be changed to
2 C
4 C
The rms speed (in m/s) of oxygen molecules of the gas at temperature 300 K, is
483
504
377
346
If we change the value of R, then
voltage does not change on L
voltage does not change on LC combination
voltage does not change on C
voltage changes on LC combination
A choke is preferred to a resistance for limiting current in AC circuit because
choke is cheap
there is no wastage of power
choke is compact in size
choke is a good absorber of heat
In a series L-C-R circuit, resistance R = 10 Ω and the impedance Z = 10 Ω. The phase difference between the current and the voltage is
0o
30o
45o
60o
The impedance of a circuit, when a resistance R and an inductor of inductance L are connected in series in an AC circuit of frequency f, is
Induced emf in the coil depends upon
conductivity of coil
amount of flux
rate of change of linked flux
resistance of coil