Energy and Its Sources

Q. Why is diesel engine more efficient than a petrol engine?

1. Because diesel has a lower ignition temperature than petrol.
2. Because diesel is easily available.
3. Because diesel is heavier than petrol.
4. Because it is easier to maintain.

Q.

What is a source of energy? What are the two main categories of the sources of energy?

Q.

The substance which gives heat and light after combustion is called-

Q.

Describe safety rules for electricity.

Q.

What are the advantages of compact fluorescent lamp and arc lamp?

Q.

What is energy? Explain conservation of energy with an example. [3 MARKS]

Q.

Fuel formed under the earth's surface by the decomposition of organic matter is called ___ fuel.

Q.

Choose the correct statement :

1. Sun can be taken as an inexhaustible source of energy

2. There is infinite storage of fossil fuel inside the earth

3. Hydro and wind energy plants are non polluting sources of energy

4. Waste from a nuclear power plant can be easily disposed off

Q.

What do you mean by cryogenics?

Q.

Why do we feel cool when a fan is switched on?

Q. The potential energy of an energy of an object of mass m moving in my plane in a conservative Field is given by U=ax+by, where x and y are position coordinates of an object. Find magnitude of its acceleration

Q.

Some words (underlined) in the following sentences are jumbled up. Write them in their correct form.

$\left(\mathrm{a}\right)$ Seldie is a combustible substance.

$\left(\mathrm{b}\right)$ Slags is a non-combustible material.

$\left(\mathrm{c}\right)$ Chittsmack does not burn by itself.

$\left(\mathrm{d}\right)$ Some substances on combustion produce thea and mafel.

$\left(\mathrm{e}\right)$The amount of heat energy produced on complete combustion of $1$kg of a fuel is called its Aricolci uelav.

Q.

We say energy can neither be created nor destroyed but it is interchangeable. And we know electricity is also a type of energy, so why do we say save electricity for future ?

Q. Plants convert light energy to chemical energy through photosynthesis; this is an example of:

1. Creation of energy.
2. Destruction of energy.
3. Transformation of energy from one form to another.
4. None of these.

Q. Energy can neither be created nor be destroyed.

1. False
2. True

Q.

we learnt that the total energy during a physical or chemical process is conserved. Why, then, do we hear so much about the energy crisis? If energy can neither be created nor destroyed, we should have no worries! We should be able to perform endless activities without thinking about energy resources!

Q. Question 28
What measures would you take to conserve electricity in your house?

Q. Plants convert the light energy to chemical energy through photosynthesis. During the process, total energy is conserved.

1. False
2. True

Q.

Which is the ultimate source for generating electricity?

1. Bio mass

2. None of these

3. Sun

4. Nuclear energy

Q. Heat flows from an object of temperature to an object of temperature.

1. higher
2. lower
3. zero
4. same

Q.

What are the steps to reduce consumption of coal and petroleum?

Q. Which of following relations is correct for Einstein-mass energy relation?

1. 
   $E=\Delta m{c}^2$
2. 
   $E=\Delta m^{2}c$
3. 
   $E=\Delta mc$
4. 
   $\Delta m$

Q.

Which of the following is not combustible?

1. Oxygen

2. Hydrogen

3. Butane

4. Methane

Q. Which of the following statement is true in case of steam engines?

1. Electrical energy is converted into mechanical energy.
2. Mechanical energy is converted into heat energy.
3. Heat energy is converted into mechanical energy.
4. Chemical energy is converted into electrical energy.

Q.

What do you mean by cryogenic hardening?

Q.

Which is the ultimate source of energy?

1. Water

2. Sun

3. Uranium

4. Fossil fuels

Q.

State the energy conversion for a HOT CATHODE RAY TUBE.

1. Light Energy to Heat Energy

2. Electrical Energy to Heat Energy

3. Electrical Energy to Chemical Energy

4. Chemical Energy to Heat Energy

5. Electrical Energy to Light Energy

Q.

On a bright sunny day, Shaunak was thinking why cannot we see upside down image of the sun?

1. Sun provides light to the Earth

2. Sun produces heat

3. Sun is at infinity

4. Sun is a star

Q. On burning a candle, chemical energy of the wax is converted to light energy.

1. True
2. False

Q. Which of the following are examples of fuels?

1. LPG
2. All of these
3. Petrol
4. Diesel