Turns Ratio

Q.

What is the quality factor of RLC circuit?

Q. What is the value of iota the power iota?

Q. The self-inductance of the motor of an electric fan is $10\text{H}$. In order to impart maximum power at $50\text{Hz}$, , it should be connected to a capacitance of

1. $4\mu \text{F}$
2. $8\mu \text{F}$
3. $1\mu \text{F}$
4. $2\mu \text{F}$

Q. Four ideal diodes are connected as shown in circuit.
The current through 20 $\Omega$ resistor will be

1. $0.2A$
2. $0.3A$
3. $0.5A$
4. Zero

Q.

A hot plate of an electric oven connected to a 220 $V$ line has two resistance coils A and B, each of 24 resistances, which may be used separately, in series, or in parallel. What are the currents in the three cases?

Q. Power factor of the circuit will be zero, if circuit is

1. LR
2. R
3. L
4. LCR

Q.

What are transistor parameters?

Q.

The winding of a motor has a resistance of 80 ohms at 15⁰C. Find its resistance at 50⁰ C. the temperature co-efficient of resistance is 0.004/⁰C

1. 60.57Ω

2. 80.0Ω

3. 90.56Ω

4. 75.47Ω

Q. Two copper wires have their masses in the ratio 2 : 3 and the lengths in the ratio 3 : 4. The ratio of their resistances is:

1. 27:32
2. 16:9
3. 4:9
4. 1:2

Q. For a common emitter amplifier, current gain is 60. If the emitter current is 6.6mA the collector current is

1. 0.108 mA
2. 6.492 mA
3. 1.1 mA
4. 3.3 mA

Q. In an ideal transformer, the voltage and the current in primary coil are $200\text{V}$ and $2\text{A}$ respectively. If the voltage in the secondary coil is $200\text{V}$, then the value of current in the secondary coil will be

1. $10\text{A}$
2. $20\text{A}$
3. $0.2\text{A}$
4. $2\text{A}$

Q. The number of turns in primary and secondary coils of an ideal transformer is $50$ and $200$ respectively. If the current in the primary coil is $4\text{A}.$ The current in the secondary coil is-

1. $1\text{A}$
2. $2\text{A}$
3. $4\text{A}$
4. $5\text{A}$

Q.

In the given circuit, find the power consumed by the circuit.

1. $1.07W$

2. $2.07W$

3. $3.07W$

4. $4.07W$

Q. An iron transformer assumed to be $100\%$ efficient. The ration of the secondary truns to the primary truns is $1:20$. A $240V$ ac supply is connected to the primary coil. What is the current in the primary coil?

1. $0.1A$
2. $0.14A$
3. $2A$
4. $40A$

Q. A transformer has $200$ turns in primary coil and $600$ turns in secondary coil. If a $220\text{V}$ $DC$ is applied across the primary coil, what will be the voltage across the secondary coil.

1. $\frac{220}{3}\text{V}$
2. $660\text{V}$
3. $\text{Zero}$
4. $220\text{V}$

Q. A parallel combination of an inductor coil and a resistance of $60\Omega$ is connected to an ac source. The current in the coil, current in the resistance and the source current are $3A,2.5A$ and $4.5A$ respectively. Therefore

1. kirchhoff's current law is NOT applicable to ac circuits
2. impedance of the coil is $50\Omega$
3. electric power dissipated in the coil is $150W$
4. impedance of the circuit is $33.3\Omega$

Q. A voltmeter connected to the terminals of battery reads $6\text{V}$ initially. When the lamp is lighted with the battery, same voltmeter reads $4\text{V}$. If resistance of lamp is 10 $\Omega$, resistance of battery in Ohms is

Q. The resistance of the coil of a tangent galvanometer is $60\Omega$. It is connected to a battery of negligible internal resistance. The deflection is found to be ${60}^{\circ }$. Now a shunt resistance of $30\Omega$ is connected across the coil of the tangent galvanometer. The deflection produced will be________${}^{\circ }$

Q. A coil having self-inductance $L$ is connected in series with a bulb $\text{B}$ with an AC source. Brightness of the bulb decrease when-

1. An iron rod is inserted in the coil
2. Frequency of the AC source is decreased
3. Number of turns in the coil is reduced
4. A capacitance of reactance $X_C=X_L$ included in the same circuit.

Q. A circuit, containing an inductance and a resistance connected in series, has an AC source of $200\text{V},50\text{Hz}$ connected across it. An AC rms current of $10\text{A}$ flows through the circuit and the power loss is measured to be $1\text{kW}$. Then

1. The inductance of the circuit is $\frac{\sqrt{3}}{10\pi }\text{H}$.
2. The frequency of the AC when the phase difference between the current and emf becomes $\frac{\pi }{4}$, with the above components is $\frac{50}{\sqrt{3}}\text{Hz}$
3. The frequency of AC, at which the reactive power is half of the actual power lost is $\frac{25}{\sqrt{3}}\text{Hz}$
4. The frequency of the AC when the phase difference between the current and emf becomes $\frac{\pi }{4}$, with the above components is $\frac{25}{\sqrt{3}}\text{Hz}$.

Q. A coil has a resistance of $10\Omega$ and an inductance of $0.4\text{H}$. It is connected across an AC source of $6.5\text{V},\frac{30}{\pi }\text{Hz}$. The average power consumed in the circuit is

1. $0.625\text{W}$
2. $0.325\text{W}$
3. $0.925\text{W}$
4. $0.125\text{W}$

Q. Two alternating voltage generators produce EMFs of the same amplitude $E_0$​ but with a phase difference of $\pi /3$. The magnitude of resultant EMF is

1. $\sqrt{5}{E}_0$
2. $E_0$
3. $\sqrt{2}{E}_0$
4. $\sqrt{3}{E}_0$

Q.

A $2W$ carbon resistor is color coded with green, black, red and brown respectively. The maximum current which can be passed through this resistor is :

1. $0.4mA$

2. $20mA$

3. $63mA$

4. $100mA$

Q. 4.A grinder motor is designed to operate at a current of 5 A and at a p.d. of 200 V. What resistance must be connected in series with the motor so as to maintain the rated current when it is operated on a 220 V line?

Q. A 1250 W, 115 V heater operates at 115 V. What is the resistance of the heating coil?

Q. In the circuit shown in the figure, resistors $X$ and $Y$, each with resistance $R$, are connected to a $6\text{V}$ battery of negligible internal resistance. A voltmeter, also of resistance $R$, is connected across $Y$.


What is the reading of the voltmeter ?

1. zero
2. between $0$ and $3\text{V}$
3. $3\text{V}$
4. between $3\text{V}$ and $6\text{V}$

Q. A power transmission line feeds input power at 2300 V to a stepdowntransformer with its primary windings having 4000 turns. Whatshould be the number of turns in the secondary in order to get outputpower at 230 V?

Q. For the circuit shown in the figure, the EMF of the generator is $E$. The current through the inductor is $3\text{A}$, while the current through the condenser is $1\text{A}$ then current drawn from the generator is

Q. A generator produces time varying voltage given by $E=240\sin 120t$, where $t$ is in second. The average value of voltage for the half cycle is -

1. $123\text{V}$
2. $133\text{V}$
3. $143\text{V}$
4. $153\text{V}$

Q.

In the circuit shown in the adjacent figure, the batteries are ideal. The charge on the capacitor C is

1. $10\mu C$

2. zero

3. $20\mu C$

4. $30\mu C$