1
MCQ (Single Correct Answer)
If the rms current in a 50 Hz AC circuit is 5 A , the value of the current $1 / 300 \mathrm{~s}$ after its value becomes zero is
A
$5 \sqrt{2} \mathrm{~A}$
B
$5 \sqrt{3 / 2} \mathrm{~A}$
C
$5 / 6 \mathrm{~A}$
D
$5 / \sqrt{2} \mathrm{~A}$
2
MCQ (Single Correct Answer)
An alternating current generator has an internal resistance $R_g$ and an internal reactance $X_g$. It is used to supply power to a passive load consisting of a resistance $R_g$ and a reactance $X_L$. For maximum power to be delivered from the generator to the load, the value of $X_L$ is equal to
A
zero
B
$X_g$
C
$-X_g$
D
$R_g$
3
MCQ (Single Correct Answer)
When a voltage measuring device is connected to $A C$ mains, the meter shows the steady input voltage of 220 V . This means
A
input voltage cannot be $A C$ voltage, but a DC voltage
B
maximum input voltage is 220 V
C
the meter reads not $v$ but $< v^2>$ and is calibrated to read $\sqrt{< v^2>}$
D
the pointer of the meter is stuck by some mechanical defect
4
MCQ (Single Correct Answer)
To reduce the resonant frequency in an $L-C-R$ series circuit with a generator
A
the generator frequency should be reduced
B
another capacitor should be added in parallel to the first
C
the iron core of the inductor should be removed
D
dielectric in the capacitor should be removed
5
MCQ (Single Correct Answer)
Which of the following combinations should be selected for better tuning of an $L-C-R$ circuit used for communication?
A
$R=20 \Omega, L=1.5 \mathrm{H}, C=35 \propto \mathrm{~F}$
B
$R=25 \Omega, L=2.5 \mathrm{H}, C=45 \alpha \mathrm{~F}$
C
$R=15 \Omega, L=3.5 \mathrm{H}, C=30 \alpha \mathrm{~F}$
D
$R=25 \Omega, L=1.5 \mathrm{H}, C=45 \propto \mathrm{~F}$