A direct current of \(5~ A\) is superimposed on an alternating current \(I=10sin ~\omega t\) flowing through a wire. The effective value of the resulting current will be:
1. | \(15/2~A\) | 2. | \(5 \sqrt{3}~A\) |
3. | \(5 \sqrt{5}~A\) | 4. | \(15~A\) |
An ideal resistance \(R,\) ideal inductance \(L,\) ideal capacitance \(C,\) and AC voltmeters \(V_1, V_2, V_3~\text{and}~V_4 \)
1. | reading in \(V_3\) = reading in \(V_1\) |
2. | reading in \(V_1\) = reading in \(V_2\) |
3. | reading in \(V_2\) = reading in \(V_4\) |
4. | reading in \(V_2\) = reading in \(V_3\) |
1. | \(50\) V | 2. | \(50 \sqrt{2} ~\text{V}\) |
3. | \(100\) V | 4. | \(0\) V |
An AC voltage source is connected to a series \(LCR\) circuit. When \(L\) is removed from the circuit, the phase difference between current and voltage is \(\dfrac{\pi}{3}\). If \(C\) is instead removed from the circuit, the phase difference is again \(\dfrac{\pi}{3}\) between current and voltage. The power factor of the circuit is:
1. \(0.5\)
2. \(1.0\)
3. \(-1.0\)
4. zero
An AC ammeter is used to measure the current in a circuit. When a given direct current passes through the circuit, the AC ammeter reads \(6~\text A.\) When another alternating current passes through the circuit, the AC ammeter reads \(8~\text A.\) Then the reading of this ammeter if DC and AC flow through the circuit simultaneously is:
1. \(10 \sqrt{2}~\text A\)
2. \(14~\text A\)
3. \(10~\text A\)
4. \(15~\text A\)
The variation of EMF with time for four types of generators is shown in the figures. Which amongst them can be called AC voltage?
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(a) | (b) |
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(c) | (d) |
Choose the correct option from the given ones:
1. | (a) and (d) |
2. | (a), (b), (c), and (d) |
3. | (a) and (b) |
4. | only (a) |
The time required for a \(50\) Hz sinusoidal alternating current to change its value from zero to the rms value will be:
1. \(1 . 5 \times 10^{- 2}~\text{s}\)
2. \(2 . 5 \times 10^{- 3}~\text{s}\)
3. \(10^{- 1}~\text{s}\)
4. \(10^{- 6}~\text{s}\)
In a series \(RLC\) circuit, potential differences across \(R,L\) and \(C\) are \(30\) V, \(60\) V and \(100\) V respectively, as shown in the figure. The emf of the source (in volts) will be:
1. \(190\)
2. \(70\)
3. \(50\)
4. \(40\)