Transformer

Q.

In the circuit diagram, the current flowing through the 2 ohm resistor is 1 ampere. Then the current flowing through the other resistors will be

1. 2 A and 0.5 A

2. 1 A and 2 A

3. 2 A and 4 A

4. 1 A and 0.5 A

Q. The percentage error in measuring the voltage across a resistor 'r' by a voltmeter of resistance 'R'(current assumed to be constant) is?

Q.

Transformers are used in ____.

1. DC Circuits

2. DC Motors

3. AC Circuits

4. Both AC and DC circuits

Q. What is overloading? When does it occur? What does it cause? How can overloading be avoided?

Q.

The primary and secondary windings of a transformer are ____

1. inductively linked.

2. conductively linked.

3. not linked at all.

4. physically linked.

Q.

A microphone is a device that transforms an alternating voltage from one value to another value.

1. True

2. False

Q.

A battery of 9V is connected in series with resistor of 0.2, 0.3, 0.4, 0.5, 12 Ohm. How much current would flow through the12 Ohm resistor?

Q.

A transformer works on

1. AC only

2. DC only

3. High voltage only

4. Both A and B

Q.

A step-down transformer has $50$ turns on secondary and $1000$ turns on the primary winding. If a transformer is connected to $220V$ and $1A$ AC source, what is the output current of the transformer?

1. $\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$20$}\right.A$

2. $20A$

3. $100A$

4. $2A$

Q.

Which device works on the principle of mutual induction?

Q.

Imagine if the current in the primary coil of a transformer becomes steady, then what happens to magnetic field?

1. It becomes infinity.

2. It gets halved.

3. It becomes zero.

4. It becomes constant.

Q. The primary coil of a transformer has $1,32,000$ turns and is connected to A.C. input source of $220\text{V}$. The secondary coil has $2,400$ turns. Find the output voltage.

1. 4.0 V
2. 4.5 V
3. 6.0 V
4. 5.5 V

Q.

Change in no. of magnetic field lines induces

1. Frequency in coil

2. Resistance in coil

3. EMF in the coil

4. Both A and C

Q.

The turn ratio of a transformer is given as $2:3$. If the current through the primary coil is $3A$, then calculate the current through load resistance.

1. $1A$

2. $4.5A$

3. $2A$

4. $1.5A$

Q. The primary coil of a transformer has 100 turns and the secondary coil has 200 turns. The primary coil is connected to a size AA battery that supplies a constant voltage of 1.5 volts. What is the measured voltage across the secondary coil?

1. 3 volts
2. 0.75 volts
3. 0 volts
4. 1.5 volts

Q. what is a solonoid

Q. 2 capacitor A of 3 micro Farad and B of 2 microfarad are connected in series. A can with stand a potential difference of 3 kilovolt while B can with stand 5 kilovolt. what maximum potential difference can be applied across the combination? 1. 8kV 2. 6kV 3. 7.5kV 4. 8.3kV

Q.

The different power generating stations and distribution systems are connected by a network called :

1. Ring system

2. Power grid

3. Power distributor

4. Generator transformer

Q. The direction of induced current is given by
a) Fleming’s right hand rule
b) Fleming’s left hand rule
c) Right hand thumb rule
d) Left hand thumb rule

[1 mark]

Q.

If we keep two similar loops made up of copper and constantan in a magnetic field for same amount of time, in which loop the induced e.m.f will be greater.

Q. A thermal power plant produces electric power of $500kW$ at $2500V$. The electrical energy is transported $200km$ away for distribution at $240V$.
If the resistance of the transmission cable is $0.025\Omega /km$, how much will be the current in the distribution line?

1. 1250 A
2. 2500 A
3. 625 A
4. 1875 A

Q. c) A bulb is connected to a battery of potential difference 4 V and internal resistance 2.50A steady current of 0.5 A flows through the circuit. Calculate the resistance of the bulb

Q. What do you mean by transformer?

Q. ntThe magnetic flux through a stationary loop with resistance R varies during interval of time T as phi=at (T-t). The heat generated during this time neglecting the inductance of loop will ben ntn

Q. Transformers are used to convert high voltages to the low voltages only.

1. True
2. False

Q.

What do we mean by Voltage drop?

Q.

In a transformer, the number of turns in the primary coil are 140 and that in the secondary coil are 280. If the current in primary coil is 4 A, then the current in the secondary coil is:

1. 4 A

2. 2 A

3. 10 A

4. 6 A

Q. Which of them is not designed to break the circuit?

1. Switch
2. M.C.B
3. Transformer
4. Fuse

Q. A 10 ohm resistor is connected to 6v battery. How much is the current flowing in the resistor?
a) 0.6 amp
b) 6 amp
c) 60 amp
d) 16 amp

Q. A dynamo develops $0.5A$ at $6V$. Find the energy which it generates in $1s$