1
AIPMT 2007
+4
-1
The primary and secondary coils of a transformer have 50 and 1500 turns respectively. If the magnetic flux $$\phi$$ linked with the primary coil is given by $$\phi$$ = $$\phi$$0 + 4t, where $$\phi$$ is webers, t is time in seconds and $$\phi$$0 is a constant, the output voltage across the secondary coil is
A
120 volt
B
220 volts
C
30 volts
D
90 volts.
2
AIPMT 2007
+4
-1
What is the value of inductance L for which the current is maximum in a series LCR circuit with C = 10 $$\mu$$F and $$\omega$$ = 1000 s$$-$$1 ?
A
1 mH
B
cannot be calculated unless R is known
C
10 mH
D
100 mH
3
AIPMT 2007
+4
-1
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 amp, the efficiency of the transformer is approximately
A
50%
B
90%
C
10%
D
30%
4
AIPMT 2006
+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
EXAM MAP
Medical
NEET