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) |
1. | \(14~\text{A}\) | about2. | \(28~\text{A}\) | about
3. | \(20~\text{A}\) | about4. | cannot say |
A light bulb is rated at \(100~\text{W}\) for a \(220~\text{V}\) AC supply. The RMS current through the bulb is:
1. \(0.243\) A
2. \(0.454\) A
3. \(0.222\) A
4. \(0.312\) A
1. | \(100~\text{mA}\) | 2. | \(200~\text{mA}\) |
3. | \(20~\text{mA}\) | 4. | \(10~\text{mA}\) |
1. | \(1 / \sqrt{2}\) times the rms value of the AC source. |
2. | the value of voltage supplied to the circuit. |
3. | the rms value of the AC source. |
4. | \(\sqrt{2}\) times the rms value of the AC source. |
An AC source is rated \(220~\mathrm{V}\), \(50~\mathrm{Hz}\). The average voltage is calculated in a time interval of \(0.01~\mathrm{s}\). It,
1. | must be zero |
2. | may be zero |
3. | is never zero |
4. | \(220\sqrt{2}\) V | is
A \(15.0~\mathrm{\mu F}\) capacitor is connected to a \(220~\mathrm{V}\), \(50~\mathrm{Hz}\) source. If the frequency is doubled, what happens to the capacitive reactance and the current?
1. | the capacitive reactance is halved and the current is doubled. |
2. | the capacitive reactance is doubled and the current is halved. |
3. | the capacitive reactance remains the same and the current is doubled. |
4. | the current remains the same and the capacitive reactance is halved. |
A resistor of \(200~\mathrm{\Omega}\) and a capacitor of \(15.0~\mu\text{F}\) are connected in series to a \(220~\text{V}\), \(50\) Hz AC source. The voltage (RMS) across the resistor and the capacitor are respectively:
1. \( 160.3 ~\text{V}, 160.3 ~\text{V} \)
2. \( 151 ~\text{V}, 151 ~\text{V} \)
3. \( 160.3 ~\text{V}, 151 ~\text{V} \)
4. \( 151 ~\text{V}, 160.3 ~\text{V}\)
1. | \(60^\circ\) | 2. | \(90^\circ\) |
3. | \(30^\circ\) | 4. | \(45^\circ\) |