Energy Transformation

Q.

The energy conversion in a steam engine is

1. kinetic energy into heat energy

2. heat energy into electrical energy

3. heat energy into wind energy

4. heat energy into kinetic energy

Q. What do you mean by transformation of energy

Q.

The energy conversion in an electric motor is

1. electrical to mechanical

2. mechanical to electrical

3. mechanical to heat

4. electrical to heat

Q.

What are the various forms of energy ? Give some examples of each.

Q.

write the energy transformation that takes place in the following :

Steam engine

Q. Give three examples of transformation of energy to show energy provides different forms of energy

Q. An arrow moves forward when released from a stretched bow. Explain the transformation of energy in the process.

Q. Which among the following is the correct sequence of transformation of energy in a thermal power plant?

1. Heat energy $\to$ Chemical energy $\to$ Electrical energy
2. Electrical energy $\to$ Heat energy $\to$ Chemical energy
3. Chemical energy $\to$ Heat energy $\to$ Electrical energy
4. Chemical energy $\to$ Electrical energy $\to$ Heat energy

Q.

An dc motor converts direct current energy from a battery into ____ energy of rotation.

1. Mechanical

2. Magnetic

3. Electrostatic

4. Thermal

Q. Which among the following types of energy transformation takes place in a moving vehicle?

1. Electrical energy to chemical energy
2. Heat energy to chemical energy
3. Heat energy to Nuclear energy
4. Chemical energy to kinetic energy

Q.

___ is a device which converts electrical energy into mechanical energy.

Q.

Commercial electric motors do not use a permanent magnet to rotate the armature.

1. True

2. False

Q. Which of the following devices work on the heating effect of electric current?

1. Fan
2. Radio
3. Geyser
4. Phone
5. Bulb
6. Oven
7. Switch
8. Electric iron
9. Cell
10. Toaster

Q.

For work to be done, energy must be

1. transferred from one place to another

2. transformed from one form to another

3. created

4. destroyed

Q.

What is the maximum thermal efficiency for a heat engine?

Q.

A man eats glucose and then he makes a block move, which then comes to rest after sliding on a rough floor. The correct order of energy changes can be:

1. Potential - Heat - Kinetic

2. Chemical - Kinetic - Heat

3. Heat - Kinetic - Chemical

4. Potential - Kinetic - Chemical

Q. Which of the following statements is true regarding the potential energy of a system?

1. The potential energy of a system can convert into kinetic energy.
2. The potential energy of a system always remains negative.
3. The potential energy of a body depends on its speed.
4. The potential energy of a system always remains positive.

Q. When a person speaks in front of a microphone, the sound energy converts into:

1. Magnetic energy
2. Light energy
3. Electrical energy
4. Chemical energy

Q.

Shishir was playing with a spring. He was compressing and releasing it. Suddenly he noticed that a ball, when kept on a spring, attains a certain height after it is compressed and released. In which of the following heights attained by the ball, Shishir has to spend the maximum of his energy?

1. 7m

2. 9m

3. 5m

4. 3m

Q.

Give two differences between a d.c. motors and a.c. generator.

Q. An arrow moves forward when released from a stretched bow. Explain the transformation of energy in the process.

Q.

An isolated village uses wind turbines to get electricity for street lights. What will be the energy changes that take place during the process?

1. Kinetic energy from wind - Light energy - Electrical energy

2. Kinetic energy from wind - Electrical energy - Light energy

3. Light energy - Electrical energy - Kinetic energy from wind

4. Electrical energy - Light energy - Kinetic energy from wind

Q. An elevator of height 10 m and mass 100 kg starts from the ground floor and goes to the top floor of a building 100 m in height. If the distance is covered in 100 seconds, find the power consumed by the elevator to complete this process. (Take g = 10 m/s${}^2$)

1. 1000 W
2. 900 W
3. 90, 000 W
4. 9, 000, 000 W

Q.

Which of the following is an example of conversion of mechanical energy to electrical energy ?

1. Working of loud speaker

2. Working of dynamo

3. Working of electric iron

4. Working of motor

Q.

A steam engine converts mechanical energy to heat energy.

1. True
2. False

Q. An elevator of height 10 m and mass 100 kg starts from the ground floor and goes to the top floor of a building 100 m in height. If the distance is covered in 100 seconds, find the power consumed by the elevator to complete this process. (Take g = 10 m/s${}^2$)

1. 1000 W
2. 900 W
3. 90, 000 W
4. 9, 000, 000 W

Q. Name the original source of wind energy.

Q. Sam has participated in a 100 m race in his school. If he expensed 450 W power in just the first 2 seconds of the race, then calculate his final velocity after 2 seconds.
Mass of Sam = 50 kg

Q.

Write about any three sources of heat.

Q. Complete the following sentence:
The conversion of part of energy into an undesirable form is called ______ .

1. degradation of energy.
2. generation of energy
3. useless energy
4. All of the above