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. | \(\frac{R}{4}\) |
2. | \(\frac{R}{2}\) |
3. | \(R\) |
4. | Cannot be found with the given data |
The phase difference between the current and voltage of LCR circuit in series combination at resonance is
1. 0
2. π/2
3. π
4. –π
In a series resonant circuit, the ac voltage across resistance R, inductance L and capacitance C are 5 V, 10 V and 10 V respectively. The ac voltage applied to the circuit will be
1. 20 V
2. 10 V
3. 5 V
4. 25 V
In a series LCR circuit, resistance R = 10Ω and the impedance Z = 20Ω. The phase difference between the current and the voltage is
1. 30°
2. 45°
3. 60°
4. 90°
In the circuit shown below, the AC source has voltage \(V = 20\cos(\omega t)\) volts with \(\omega =2000\) rad/sec. The amplitude of the current is closest to:
1. \(2\) A
2. \(3.3\) A
3. \(\frac{2}{\sqrt{5}}\)
4. \(\sqrt{5}~\text{A}\)