9
MCQ (Multiple Correct Answer)
In an alternating current circuit consisting of elements in series, the current increases on increasing the frequency of supply. Which of the following elements are likely to constitute the circuit?
A
Only resistor
B
Resistor and an inductor
C
Resistor and a capacitor
D
Only a capacitor
10
MCQ (Multiple Correct Answer)
Electrical energy is transmitted over large distances at high alternating voltages. Which of the following statements is (are) correct?
A
For a given power level, there is a lower current
B
Lower current implies less power loss
C
Transmission lines can be made thinner
D
It is easy to reduce the voltage at the receiving end using step-down transformers
11
MCQ (Multiple Correct Answer)
For a $L-C-R$ circuit, the power transferred from the driving source to the driven oscillator is $P=I^2 Z \cos \phi$.
A
Here, the power factor $\cos \phi \geq 0, P \geq 0$
B
The driving force can give no energy to the oscillator $(P=0)$ in some cases
C
The driving force cannot syphon out $(P<0)$ the energy out of oscillator
D
The driving force can take away energy out of the oscillator
12
MCQ (Multiple Correct Answer)
When an $A C$ voltage of 220 V is applied to the capacitor $C$
A
the maximum voltage between plates is 220 V
B
the current is in phase with the applied voltage
C
the charge on the plates is in phase with the applied voltage
D
power delivered to the capacitor is zero
13
MCQ (Multiple Correct Answer)
The line that draws power supply to your house from street has
A
zero average current
B
220 V average voltage
C
voltage and current out of phase by $90 \Upsilon$
D
voltage and current possibly differing in phase $\phi$ such that $|\phi|<\frac{\pi}{2}$