Energy

Q. The SI unit of energy is.

1. Newton
2. Joule
3. Pascal

Q.

A car is running at a speed of 15 km/h while another car of the same mass is moving at a speed of 30 km/hr. Find the ratio of their kinetic energy.

Q.

Two bodies of masses m and 4 m are moving with equal kinetic energy. The ratio of velocities with which they are traveling is :

1. 3:4

2. 2:1

3. 1:2

4. 4:5

Q. Energy can neither be created nor destroyed i.e. the total energy of an isolated system remains constant; however, it transforms from one form to another. The same phenomena can be applied when we burn a candle, chemical energy of wax is spent and converted to light energy.

1. False
2. True

Q.

State the S.I. unit of energy.

Q.

Assuming the electric consumption per day to be 12 kWh and the rate of electricity to be Rs 6.25 per unit, find how much money is to be paid in a month of 30 days.

Q.

When we burn a candle, chemical energy of wax is spent and converted to light energy.

1. True

2. False

Q.

An electric bulb converts electrical energy into ___ energy.

1. Potential

2. Light

3. Mechanical

4. Kinetic

Q.

One day the meter reading is found to be 7643 units while the next day, it was 7657 units. What is the consumption of electricity in a day?

Q.

How is work related to energy ?

Q. What is HP

Q.

State true or false.
Energy is the ability or capacity to do work.

1. True

2. False

Q.

Define 1 joule of energy.

Q.

The SI unit of energy is:

1. watt

2. newton

3. joule

4. pascal

Q. What is the definition of 1 joule ? Please explain.

Q.

(1) if you heated a big stone and a small stone in a fire, which would store more energy?explain

(2) a car and a heaavy truck are moving along a main road side by side. which has more kinetic energy explain

Q. When a tubelight is switched on, the energy gets converted from electrical energy to:

1. chemical energy
2. light energy
3. heat energy
4. kinetic energy

Q.

What is meant by transformation of energy

Q.

State the Law of conservation of energy

Q.

Which of the following energies do water stored in a dam and the water flowing from it contain respectively?

1. water stored in a dam - potential energy, water flowing from a dam - kinetic energy

2. water stored in a dam - kinetic energy, water flowing from a dam - potential energy

3. both contain potential energy

4. both contain kinetic energy

Q.

Define the term energy.

Q.

How does the kinetic energy of an object change, when its (i) mass alone is doubled and (ii) speed alone is doubled?

Q.

If we jump from one or two stairs we don't get hurt but if we jump from a building we get hurt .Why?

Q. Arrange in decreasing order of magnitude: P= Parsec, Q = Astronomical unit, R = light year

1. P Q R
2. Q P R
3. P R Q
4. Q R P

Q.

Two toy-cars A and B of masses 200 g and 500 g respectively are moving with the same speed. Which of the two has greater kinetic energy ?

Q. How is temperature related to heat ?

Q.

The mechanical energy of a train moving on the ground is only in the form of its potential energy.

1. True

2. False

Q.

An electrical bulb glows because electrical energy changes into

1. light energy first

2. heat energy first

3. chemical energy first

4. none of these

Q.

Energy is the capacity of doing work.

1. True

2. False

Q. A certain household has consumed $250$ units of energy during a month. How much energy is this in joule ?

1. $9\times {10}^{8}J$
2. $10\times {10}^{8}J$
3. $9\times {10}^{7}J$
4. $9\times {10}^{-8}J$