Energy Transformation

Q.

When an arrow is shot from a bow, it has kinetic energy in it. This kinetic energy is acquired from

1. The mass energy of the stretched bow

2. The gravitational potential energy of the bow

3. The elastic potential energy of the stretched bow

4. The inherent mass energy of the arrow

Q.

In what way does the temperature of water at the bottom of a waterfall differ from the temperature at the top? Explain the reason.

Q.

State the energy changes in the following cases while in use:

(a) loudspeaker

(b) a steam engine

(c) microphone

(d) washing machine

(e) a glowing electric bulb

(f) burning coal

(g) a solar cell

(h) bio-gas burner

(i) an electric cell in a circuit

(j) a petrol engine of a running car

(k) an electric toaster

(l) a photovoltaic cell

(m) an electromagnet.

Q.

What do you mean by degradation of energy?Explain it by taking one example of your daily life.

Q. Question 3
The device used for producing electric current is called a
(a) generator
(b) galvanometer
(c) ammeter
(d) motor

Q.

When an arrow is shot from a bow, it has kinetic energy in it.Explain briefly from where does it get its kinetic energy.

Q. The conversion of energy that takes place in a battery is:

1. Mechanical to Chemical
2. Chemical to Heat
3. Chemical to Electrical
4. Heat to Electrical

Q.

What are (i) translational, (ii) rotational and (iii) vibrational, kinetic energies. Give at least one example of each.

Q.

Is it practically possible to convert a form of energy completely into the other useful form? Explain your answer.

Q.

State the energy changes taking place when a toy car spring is wound and the car is made to move on level floor.

Q.

Give one example when heat energy changes into kinetic energy.

Q.

When a body falls freely, its potential energy is converted into kinetic energy. But when the freely falling body reaches the ground, it comes to rest. What happens to the kinetic energy of the body when it stops on reaching the ground?

Q.

In an electric cell while in use, the change in energy is from:

(a) electrical to mechanical

(b) electrical to chemical

(c) chemical to mechanical

(d) chemical to electrical

Q.

Name the energy transformation that occur in electrical cell

Q.

Kinetic Energy of a rotating body i.e. Rotational Kinetic Energy can be converted to various forms of energy they are

Q.

Name the form of energy in which potential energy can change.

Q.

Arrange the following changes of energy during the following phase transition in proper order. Ice(0⁰C)$\to$Water(50⁰C)$\to$Ice(0⁰C)

(1) Potential energy increases and kinetic energy remains constant

(2) Potential energy decreases and kinetic remains constant

(3) Potential energy increases and kinetic energy increases

(4) Potential energy decreases and kinetic energy decreases

1. 4 2 3 1

2. 1 3 2 4

3. 1 3 4 2

4. 3 4 2 1

Q. What is heating effect of electric current? What is its origin?

Q.

The kinetic energy increases with an increase is in temperature.

1. True
2. False

Q. Question 14
Choose the incorrect statement regarding wind power.

(a) It is expected to harness wind power to minimum in open space.
(b) The potential energy content of wind blowing at high altitudes is the source of wind power.
(c) Wind hitting at the blades of a windmill causes them to rotate The rotation thus achieved can be utilised further.
(d) One possible method of utilising the energy of rotational motion of the blades of a windmill is to run the turbine.

Q.

What is the type of energy associated with the flowing water?

Q.

Complete the following sentence:

The conversation of part of energy into an undesirable form is called ..............

Q.

A freely falling body stops on reaching the ground. What happened to its kinetic energy?

Q. The conversion of energy that takes place in a battery is:

1. Mechanical to Chemical
2. Chemical to Heat
3. Heat to Electrical
4. Chemical to Electrical

Q. Working of electric generator and electric motor

Q.

A man consumes glucose and then he moves a block which then comes to rest after sliding on a rough floor. The correct order of energy changes can be

1. chemical - kinetic - heat

2. heat - kinetic - chemical

3. data insufficient

4. chemical - heat - kinetic

Q.

A battery lights a bulb. Describe the energy change involved in the process.

Q.

The temperature of water at the bottom of a waterfall is higher than that of the water at the top, because

1. falling water absorbs heat from the sun

2. kinetic energy of the falling water is converted into heat

3. water at the bottom has greater potential energy

4. the rocks on the river bed give out heat

Q. When an arrow in shot-from its bow, it has kinetic energy. From where does it get the kinetic energy?

Q. What is the principal of electric motor