Energy

Q.

An electric motor takes 5 A from a 220 V line. Determine the power of the motor and the energy consumed in 2 h.

Q.

One joule is equal to how many erg?

Q. An electric heater draws a current of 10A from a 220V supply. What is the cost of using the heater 5 hrs per day for 30 days if the cost of 1 unit is RS. 2.50?

Q. is the device which converts mechanical energy to electrical energy.

1. Dynamo
2. Boiler
3. Heater

Q.

Define a kilowatt hour. How is it related to joule?

Q.

How is One kilowatt hour related to joule

1. 1 kWh = 3.6 x 10^-6 J

2. 1 kWh = 3.6 x 10⁵ J

3. 1 kWh = 3.6 x 10⁶ J

4. 1 kWh = 3.6 x 10⁸ J

Q.

Name the largest and smallest practical units of energy.

Q.

Define energy

Q.

Which is the ultimate source of energy on earth?

1. Sun

2. Water

3. Uranium

4. Fossil fuels

Q.

Statement 1: Energy can neither be created nor destroyed.
Statement 2: Energy cannot be converted from one form to another.

1. Only statement​ 1 is correct.

2. Only statement​ 2 is correct.

3. Both statements are wrong.

4. Both statements are correct.

Q.

An engine can pump 30000L of water to a vertical height of 45 m in 10 minutes. Calculate the work done by the machine and its power.

Q.

6.4 kJ of energy causes a displacement of 64 m in a body in the direction of force in 2.5 seconds. Calculate the Power in horsepower (HP). (Take 1 HP = 746 W)

1. 6.4 HP

2. 640 HP

3. 343 HP

4. 3.43 HP

Q.

Define the term energy and state its S.I. unit.

Q.

A small speaker delivers $2W$of audio output. At what distance from the speaker will one detect $120dB$ intensity sound? (Given reference intensity of sound is ${10}^{-12}W/m^2$)

1. $40cm$

2. $20cm$

3. $10cm$

4. $30cm$

Q.

Name six different forms of energy?

Q.

What does it mean when Gibbs free energy is 0?

Q.

Write the energy transformation in a thermal power plant.

Q.

'Sun is the ultimate source of energy.' Comment

Q.

What is the ratio of 1 kWh to 1 MeV?

Q.

Define the term calorie. How is it related to joule?

Q. What is short circuit current in a solar cell and how current is possible when potential difference is zero in that case?

Q.

What is the S.I. unit of energy and power?

Q. Light is a form of energy. Energy not be created nor be destroyed. When light ray falls on any surface some or more amount of light get absorb. How?

Q.

Express joule in terms of erg.

Q.

What is the difference between free energy and activation energy?

Q.

Is Gibbs free energy always negative

Q.

One form of energy cannot be transformed to another form of energy.

1. True
2. False

Q.

Most of the energy we use originally comes from

1. oceans

2. sun

3. air

4. soil

Q.

Which among the following sources of energy are renewable?

1. 1, 2 and 5

2. 1, 2 and 3

3. 3, 4 and 5

4. 1, 2 and 4

Q.

1 horsepower is equal to $746J$ .

1. True
2. False