1
AIPMT 2006
MCQ (Single Correct Answer)
+4
-1
The core of a transformer is laminated because
A
ratio of voltage in primary and secondary may be increased
B
energy losses due to eddy currents may be minimised
C
the weight of the transformer may be reduced
D
rusting of the core may be prevented.
2
AIPMT 2006
MCQ (Single Correct Answer)
+4
-1
A coil of inductive reactance 31 $$\Omega $$ has a resistance of 8 $$\Omega $$. It is placed in series with a condenser of capacitative reactance 25 $$\Omega $$. The combination is connected to an a.c. source of 110 V. The power factor of the circuit is
A
0.33
B
0.56
C
0.64
D
0.80
3
AIPMT 2005
MCQ (Single Correct Answer)
+4
-1
In a circuit L, C and R are connected in series with an alternating voltage source of frquency $$f.$$ The current leads the voltage by 45o. The value of C is
A
$${1 \over {\pi f\left( {2\pi f\,L - R} \right)}}$$
B
$${1 \over {2\pi f\left( {2\pi f\,L - R} \right)}}$$
C
$${1 \over {\pi f\left( {2\pi f\,L + R} \right)}}$$
D
$${1 \over {2\pi f\left( {2\pi f\,L + R} \right)}}$$
4
AIPMT 2004
MCQ (Single Correct Answer)
+4
-1
A coil of 40 henry inductance is connected in series with a resistance of 8 ohm and the combination is joined to the terminals of a 2 volt battery. The time constant of the circuit is
A
5 seconds
B
1/5 seconds
C
40 seconds
D
20 seconds
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