1
AIEEE 2010
+4
-1
In a series $$LCR$$ circuit $$R = 200\Omega$$ and the voltage and the frequency of the main supply is $$220V$$ and $$50$$ $$Hz$$ respectively. On taking out the capacitance from the circuit the current lags behind the voltage by $${30^ \circ }.$$ On taking out the inductor from the circuit the current leads the voltage by $${30^ \circ }.$$ The power dissipated in the $$LCR$$ circuit is
A
$$305$$ $$W$$
B
$$210$$ $$W$$
C
$$zero$$ $$W$$
D
$$242$$ $$W$$
2
AIEEE 2010
+4
-1
A rectangular loop has a sliding connector $$PQ$$ of length $$l$$ and resistance $$R$$ $$\Omega$$ and it is moving with a speed $$v$$ as shown. The set-up is placed in a uniform magnetic field going into the plane of the paper. The three currents $${I_1},{I_2}$$ and $$I$$ are A
$${I_1} = - {I_2} = {{Blv} \over {6R}},\,\,I = {{2Blv} \over {6R}}$$
B
$${I_1} = {I_2} = {{Blv} \over {3R}},\,\,I = {{2Blv} \over {3R}}$$
C
$${I_1} = {I_2} = I = {{Blv} \over R}$$
D
$${I_1} = {I_2} = {{Blv} \over {6R}},I = {{Blv} \over {3R}}$$
3
AIEEE 2010
+4
-1
In the circuit shown below, the key $$K$$ is closed at $$t=0.$$ The current through the battery is A
$${{V{R_1}{R_2}} \over {\sqrt {R_1^2 + R_2^2} }}$$ at $$t=0$$ and $${V \over {{R_2}}}$$ at $$t = \infty$$
B
$${V \over {{R_2}}}$$ at $$\,t = 0$$ and $${{V\left( {{R_1} + {R_2}} \right)} \over {{R_1}{R_2}}}$$ at $$t = \infty$$
C
$${V \over {{R_2}}}$$ at $$\,t = 0$$ and $${{V{R_1}{R_2}} \over {\sqrt {R_1^2 + R_2^2} }}$$ at $$t = \infty$$
D
$${{V\left( {{R_1} + {R_2}} \right)} \over {{R_1}{R_2}}}$$ at $$t=0$$ and $${V \over {{R_2}}}$$ at $$t = \infty$$
4
AIEEE 2009
+4
-1
An inductor of inductance $$L=400$$ $$mH$$ and resistors of resistance $${R_1} = 2\Omega$$ and $${R_2} = 2\Omega$$ are connected to a battery of $$emf$$ $$12$$ $$V$$ as shown in the figure. The internal resistance of the battery is negligible. The switch $$S$$ is closed at $$t=0.$$ The potential drop across $$L$$ as a function of time is : A
$${{12} \over t}{e^{ - 3t}}V$$
B
$$6\left( {1 - {e^{ - t/0.2}}} \right)V$$
C
$$12{e^{ - 5t}}V$$
D
$$6{e^{ - 5t}}V$$
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