Q. No.
The peak value of an alternating e.m.f. E is given by is 10 volts and its frequency is 50 Hz. At time , the instantaneous e.m.f. is
1. 10 V
2.
3. 5 V
4. 1 V
If a current I given by flows in an ac circuit across which an ac potential of has been applied, then the power consumption P in the circuit will be
1.
2.
3.
4. P = 0
| 1. | \( 0.2~\text{sec}\) | 2. | \( 0.25~\text{sec}\) |
| 3. | \(25 \times10^{-3}~\text{sec}\) | 4. | \(2.5 \times10^{-3}~\text{sec}\) |
1. \(R + 2\pi f L\)
2. \(\sqrt{R^{2} + 4 \pi^{2} f^{2} L^{2}}\)
3. \(\sqrt{R^{2} + L^{2}}\)
4. \(\sqrt{R^{2} + 2 \pi f L}\)
A resistance of \(300~\Omega\) and an inductance of \(\frac{1}{\pi}\) henry are connected in series to an AC voltage of \(20\) volts and a \(200\) Hz frequency. The phase angle between the voltage and current will be:
| 1. | \(\tan^{- 1} \dfrac{4}{3}\) | 2. | \(\tan^{- 1} \dfrac{3}{4}\) |
| 3. | \(\tan^{- 1} \dfrac{3}{2}\) | 4. | \(\tan^{- 1} \dfrac{2}{5}\) |
In a region of uniform magnetic induction B = 10–2 tesla, a circular coil of radius 30 cm and resistance π2 ohm is rotated about an axis that is perpendicular to the direction of B and which forms a diameter of the coil. If the coil rotates at 200 rpm the amplitude of the alternating current induced in the coil is :
1. 4π2 mA
2. 30 mA
3. 6 mA
4. 200 mA
In a LCR circuit having L = 8.0 henry, C = 0.5 μF and R = 100 ohm in series. The resonance frequency in radian per second is
1. 600 radian/second
2. 600 Hz
3. 500 radian/second
4. 500 Hz
The impedance of a circuit consists of 3 ohm resistance and 4 ohm reactance. The power factor of the circuit is :
1. 0.4
2. 0.6
3. 0.8
4. 1.0
The power factor of a good choke coil is:
1. Nearly zero
2. Exactly zero
3. Nearly one
4. Exactly one
1. \(LC\)
2. \((LC)^{\frac{-1}{2}}\)
3. \(\left(\frac{L}{C}\right)^{\frac{-1}{2}}\)
4. \(\frac{C}{L}\)
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