CBSE
Multiple Choice QuestionsIf an ideal parallel LC circuit, the capacitor is changed by connecting it to a d.c source which is then disconnected. The current in the circuit
becomes zero instantaneously
grows monotonically
decays monotonically
oscillates instantaneously
Assertion: The alternating current lags behind the e.m.f. by a phase angle of /2, when AC flows through an inductor.
Reason: The inductive reactance increases as the frequency of AC source decreases.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
In an AC circuit the potential differences across an inductance and resistance joined in series are respectively 16 V and 20 V. The total potential difference of the source is
20.0 V
25.6 V
31.9 V
53.5 V
When 100 V d.c is applied across a coil, a current of 1 A nows through it. When 100 V a.c. of 50 Hz is applied to the same coil only 0.5 A flows. The inductance of the coil is
0.55 H
5.5 H
0.55 mH
55 mH
The circuit shown in the figure acts as
tuned filter
low pass filter
high pass filter
rectifier
Assertion: No power loss associated with pure capacitor in ac circuit.
Reason: No current is flowing in this circuit.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
The focal length of the objective and eye lenses of a microscope are 1.6 cm and 2.5 cm respectively. The distance between the two lenses is 21. 7 cm. If the final image is formed at infinity. What is the linear magnification?
11
110
1.1
44
A bulb and a condenser are connected in with an A>C source. On increasibg the frequency will
increase
decrease
sometimes increase and sometimes decrease
neither increase nor decrease.
What is the dimensions of impedance ?
[ M L2 T-3 A-2 ]
[ M-1 L-2 T3 A2 ]
[ M L3 T-3 A-2 ]
[ M-1 L-3 T3 A2 ]
A 50 Hz a.c source of 20 volts is connected across R and C as shown in figure. The volage across R is 12 volt. The voltage across C is
8 V
16 V
10 V
not possible to determine unless values of R and C are given
