Power Transmission

Q.

Why AC is more dangerous than DC?

Q.

Why Transformer Rating is in kVA not in kW?

Q.

What is the voltage at which the electric power is generated at the generating station?

1. 11000 V

2. 1100 V

3. 11 KV

4. 11100 V

Q.

The frequency of power supply used in India is _____ Hz.

1. 60

2. 240

3. 440

4. 50

Q.

What is the function of a transformer?

1. It converts AC to DC

2. It converts DC to AC

3. To Step down or up the DC voltages

4. To Step down or up the AC voltages

Q.

Why Step Down Transformer is Used in Rectifier

Q.

Why is the electric power from the generating station transmitted at a high voltage?

1. To increase energy loss

2. To decrease energy loss

3. Less risk of electric shocks

4. High voltage is easy to transmit

Q.

How the earth wire prevents electric shocks?

Q.

Which quantity is increased in the step-down transformer?

1. Current

2. Voltage

3. Power

4. Frequency

Q. What is a transformer? Explain the principle, construction, working and theory of a transformer.

Q.

How do you test an inductor?

Q.

Give two characteristics of a high tension wire.

Q.

An electric motor is rated 1.5 KW 250V.Calculate a)current flowing into the motor b)energy consumed by it in one second c)the time in which it will consume 90 kWh of energy

Q. (a) What is the meaning of electric power of an electrical device? Write its SI unit.

(b) An electric kettle of $2kW$ is used for $2h$. Calculate the energy consumed in
(i) kilowatt hour and
(ii) joules.

Q.

Does Inductance depend on the Frequency ?

Q.

The voltage of power generated at the generating stations is first stepped up before its transmission. Give reason.

Q. Delta connection is desirable for transmission of electrical energy to distant places.

1. True
2. False

Q.

What is a transformer and what are its types?

Q.

How does an inductor smooth current?

Q.

Various components of a step-down transformer are

1. Laminated Soft Iron Core, thicker Primary Coil with more turns than thinner Secondary coil

2. Laminated Soft Iron Core, thinner Primary Coil with more turns than thicker Secondary coil

3. Laminated Soft Iron Core, thicker Primary Coil with less turns than thinner Secondary coil

4. Laminated Soft Iron Core, thinner Primary Coil with less turns than thicker Secondary coil

Q. At which stage of the power transmission is the step-up transformer used?

1. At a sub-station
2. Before transmitting power to a long distance
3. After transmitting power to a long distance
4. Before the distribution transformer

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.

What are high tension wire? Give two characteristics of these wire.

Q.

Bonding element in a strain gauge must have __________.

1. Low insulation resistance

2. High insulation resistance

3. Zero insulation resistance

4. Infinite insulation resistance

Q.

Can a transformer convert AC to DC?

Q.

Two light bulbs are marked 230 V; 75 W and 230 V; 150 W. If the first bulb has a resistance R, then the resistance of the second is;

1. (1/4) R

2. (1/2)R

3. 4R

4. 2R

Q.

High tension wires are wires having_____.

Q. What is electric energy?

Q. Why is electric power transmitted over long distances at high voltage?

1. To minimize power loses due to Joule's heating
2. To balance power loses due to Joule's heating
3. To maximize power loses due to Joule's heating
4. None

Q.

The voltage of power generated at the generating stations is first stepped up before its transmission. Give reason.