Inductive Reactance

Q. When an L–R combination is connected in series with 12V – 50 Hz supply, a current of 0.5A flows through the combination. The current differs in phase from applied voltage by $\frac{\pi }{3}$ rad. Then resistance is

1. $24\Omega$
2. $12\Omega$
3. $6\Omega$
4. $3\Omega$

Q. When a coil is connected to a D.C source of emf 12V, a current of 4 amp flows in it. If same coil is connected to 12V, 50Hz AC source, the current is 2.4A. The self inductance of the coil is

1. $\frac{1}{20\pi }$
2. $\frac{1}{10\pi }$
3. $\frac{1}{25\pi }$
4. $\frac{1}{5\pi }$

Q. Two inductors of self inductance $L$ each and mutual inductance $M$ are connected in series as shown in the figure.
Here ${\epsilon }_0=100V$, $R=30\Omega ,L=2mH$
$\omega ={10}^{4}rad/s$.

1. Maximum current in the circuit may be 3.33 A.
2. Maximum current in circuit wil be 2A.
3. Maximum current in the circuit may be less than 2A.
4. Source voltage is ahead of current in circuit.

Q.

A coil has an inductance of 0.7H and is joined in series with a resistance of 220 Ω. When an alternating e.m.f. of 220V at 50 c.p.s. is applied to it, then the watt less component of the current in the circuit is

1. 5 ampere

2. 0.5 ampere

3. 0.7 ampere

4. 7 ampere

Q.

In the following circuit, the supply voltage is defined as: V(t) = 230 sin( 314t - π/6) and L = 2.2H. Determine the value of the current flowing through the coil.

1. 1/3sin(314t - π /6)

2. 1/3sin(314t - 2π/3)

3. 3sin(314t - 2π/3)

4. 1/3cos(314t - 5π/6)

Q. A resistance of $300\Omega$ and an inductance of $\frac{1}{\pi }$ henry are connected in series to a ac voltage of 20 volts and 200 Hz frequency. The phase angle between the voltage and current is

1. $ta{n}^{-1}\frac{4}{3}$
2. $ta{n}^{-1}\frac{3}{4}$
3. $ta{n}^{-1}\frac{3}{2}$
4. $ta{n}^{-1}\frac{2}{5}$

Q. When an L–R combination is connected in series with 12V – 50 Hz supply, a current of 0.5A flows through the combination. The current differs in phase from applied voltage by $\frac{\pi }{3}$ rad. Then resistance is

1. $24\Omega$
2. $12\Omega$
3. $6\Omega$
4. $3\Omega$

Q. An ideal inductor takes a current of 10 A when connected to a 125V, 50 Hz ac supply. A pure resistor across the same source takes 12.5 A. If the two are connected in series across a 100V, 40 Hz supply, the current through the circuit will be

1. 7A
2. 12.5A
3. 20A
4. 25A

Q. A resistance of $300\Omega$ and an inductance of $\frac{1}{\pi }$ henry are connected in series to a ac voltage of 20 volts and 200 Hz frequency. The phase angle between the voltage and current is

1. $ta{n}^{-1}\frac{4}{3}$
2. $ta{n}^{-1}\frac{3}{4}$
3. $ta{n}^{-1}\frac{3}{2}$
4. $ta{n}^{-1}\frac{2}{5}$

Q. An ideal inductor takes a current of 10 A when connected to a 125V, 50 Hz ac supply. A pure resistor across the same source takes 12.5 A. If the two are connected in series across a 100V, 40 Hz supply, the current through the circuit will be

1. 7A
2. 12.5A
3. 20A
4. 25A