The variation of EMF with time for four types of generators is shown in the figures. Which amongst them can be called AC voltage?

(a)	(b)
(c)	(d)

1.	(a) and (d)
2.	(a), (b), (c), and (d)
3.	(a) and (b)
4.	only (a)

A circuit when connected to an AC source of \(12~\text{V}\) gives a current of \(0.2~\text{A}\). The same circuit when connected to a DC source of \(12~\text{V}\), gives a current of \(0.4~\text{A}\). The circuit is:
1. series \({LR}\)
2. series \({RC}\)
3. series \({LC}\)
4. series \({LCR}\)

A coil of inductive reactance \(31~\Omega\) has a resistance of
\(8~\Omega\). It is placed in series with a condenser of capacitive reactance \(25~\Omega\). The combination is connected to an a.c. source of
\(110~\text{V}\). The power factor of the circuit is:
1. \(0.56\)
2. \(0.64\)
3. \(0.80\)
4. \(0.33\)

The core of a transformer is laminated so that:

A transformer is used to light a \(100~\text{W}\) and \(110~\text{V}\) lamp from a \(220~\text{V}\) main. If the main current is \(0.5~\text{A}\), the efficiency of the transformer is approximately:
1. \(30\%\)
2. \(50\%\)
3. \(90\%\)
4. \(10\%\)

What is the value of inductance L for which the current is maximum in a series LCR circuit with C = 10 μF and ω=1000 s^-1?

1. 100 mH

2. 1 mH

3. cannot be calculated unless R is known

4. 10 mH

In an AC circuit, the emf (e) and the current (I) at any instant are given respectively by 
e = E₀sin$\mathrm{\omega }$t 
I = I₀sin$\left(\mathrm{\omega t}-\mathrm{\varphi }\right)$ 
The average power in the circuit over one cycle of AC is:

1.  $\frac{{\mathrm{E}}_{\mathrm{o}}{\mathrm{I}}_{\mathrm{o}}}{2}$

2.  $\frac{{\mathrm{E}}_{\mathrm{o}}{\mathrm{I}}_{\mathrm{o}}}{2}$ $\sin$ $\mathrm{\varphi }$

3.  $\frac{{\mathrm{E}}_{\mathrm{o}}{\mathrm{I}}_{\mathrm{o}}}{2}$ $\cos$ $\mathrm{\varphi }$

4.  ${\mathrm{E}}_{\mathrm{o}}{\mathrm{I}}_{\mathrm{o}}$

The power dissipated in an L-C-R series circuit connected to an AC source of emf E is:

A \(220\) V input is supplied to a transformer. The output circuit draws a current of \(2.0\) A at \(440\) V. If the efficiency of the transformer is \(80\)%, the current drawn by the primary windings of the transformer is:
1. \(3.6\) A
2. \(2.8\) A
3. \(2.5\) A
4. \(5.0\) A

In the given circuit, the reading of voltmeter V₁ and V₂ are 300 V each. The reading of the voltmeter V₃ and ammeter A are respectively:

1. 150 V, 2.2 A

2. 220 V, 2.2 A

3. 220 V, 2.0 A

4. 100 V, 2.0 A