# CBSE Solutions for Class 10 Maths

#### Select CBSE Solutions for class 10 Subject & Chapters Wise :

What kind of mirror-concave, convex or plane – would be the best suited for use in a solar cooker ? Why ?

A concave mirror would be best suited in a solar cooker because it focuses the sunlight in a very small area of the solar cooker and a high temperature is produced in it which is sufficient to cook the food.

Why are we looking at alternate sources of energy ?

We are looking at alternate sources of energy because of the following reasons.
•    The fossil fuels and nuclear fuels on the earth are limited which may not last for long.
•    The undesirable effects of pollution, both from the burning of fossil fuels and from the radioactive nuclear wastes of nuclear power plants are creating threat to our environment.

If you could use any source of energy for heating your food, which one should you use and why?

I would prefer to use cooking gas like LPG. It fulfils many of the criteria of a good fuel like its ignition temperature, good calorific value and non-polluting characteristics.

What are the advantages and disadvantages of using a solar cooker? Are there places where solar cookers would have limited utility?

The heat source for a solar cooker is sunlight. It is a clean renewable and inexhaustible source of energy. As its availability is unlimited, it will be pocket-friendly.
It doesn’t work on a cloudy day.

Compare and contrast fossil fuels and the sun as direct sources of energy.

Fossil fuels are obtained from the earth’s crust as they are the remains of the dead plants and animals. They are similar to coal and petroleum and readily available for use. These are non-renewable source of energy and cannot be replenished.
Whereas solar energy is abundant in nature and can be replenished.

Hydrogen has been used as a rocket fuel. Would you consider it a cleaner fuel than CNG? Why or why not?

Hydrogen gas is cleaner than CNG as CNG contains hydrocarbons. Carbon is a form of pollutant in CNG. On the other hand, hydrogen is waste-free and the fusion of hydrogen does not produce any waste. Hence, hydrogen as a rocket fuel is cleaner than the CNG.

Can any source of energy be pollution-free? Why or why not?

No source of energy can be completely pollution-free. But solar cells are considered to be pollution-free. But their manufacturing may cause environmental damage. In case of nuclear energy, the waste produced after fusion is zero. But the wastes that are produced during fission are hazardous. Hence, no source of energy is pollution-free.

What are the advantages of nuclear energy?

Following are the advantages of nuclear energy:
•    Amount of energy produced per unit mass is large
•    As it does not produce any pollutants, it is clean
•    Fission of 1 atom of uranium produces 10 million times the energy that is obtained by burning 1 atom of carbon

What is geothermal energy?

Geothermal energy can be defined as the energy that is obtained from the earth. The energy can be obtained from the hot spots that are formed when the molten rocks at the core of the earth are pushed to the earth’s crust. Hot springs are used for the production of electricity in the geothermal power plants.

What kind of mirror – concave, convex or plain would be best suited for use in a solar cooker? Why?

For a solar cooker the heat source is sunlight for heating and cooking. The reason why a mirror is used is to reflect and focus the sunlight at one point. So a concave mirror can be used in a solar cooker, as it focuses all the sunlight at one point resulting in increase in temperature, thereby heating and cooking the food.

Why are we looking at alternate sources of energy?

The reason why we are looking at alternate sources of energy is because the fossil fuels are non-renewable sources of energy, i.e. they are not available in large quantities and cannot be replenished. Fossil fuels will get exhausted if their consumption is not controlled. Therefore, it is better to switch to alternate source of energy.

If you could use any source of energy for heating your food, which one would you use and why?

For heating and cooking, natural gas can be used for the below given reasons:
•    It is easy to use
•    It is easily available
•    Easy transportation
•    It does not produce huge amount of smoke when burnt
•    It is highly inflammable.

What is a good fuel?

A fuel is said to be good when it is easily available and when it produces a large amount of heat energy when burnt.

What is a good source of energy?

A good source of energy has the following properties:
•    Be economical
•    Easy storage and transportation
•    Easy availability
•    Work done per unit volume or mass should be large.

A …………… surface absorbs more heat as compared to a white or a reflecting surface under identical conditions.

black

…………… are the upper regions in the Earth’s crust where hot molten rocks are found.

Hot spots

A …………… consists of a structure similar to a large electric fan erected at some height on a rigid support.

windmill

…………… , …………… breakdown complex compounds in the cow dung slurry in a biogas plant to generate biogas.

Anaerobic microorganisms

We need to conserve fossil fuels because these are …………… sources of energy.

non-renewable

In a thermal power plant …………… are burnt to heat water and produce steam.

fossil fuels

Give the names of two energy sources that you would consider to be exhaustible. Give reasons for your choices.

Following are the two sources of energy that are exhaustible:

• Wood: The source of wood are forests. Due to deforestation the number of forests are reducing. We know that it takes years to grow forest. If the rate of deforestation increases, the availability of wood will decrease. Hence, wood is an exhaustible source of energy.
• Coal: The source of coal is from the dead remains of the plants and animals that remained buried for years. Industrialization has increased the demand for coal and it cannot be replenished. Hence, coal is also an exhaustible source of energy.

Match the following columns

 Column I Column II 1. Thermal power plant (a) Methane 2. Hydro power plant (b) Nuclear fission 3. Major component of biogas (c) Use coal, petroleum and natural gas to produce thermal electricity 4. Device which converts solar energy into electricity (d) Solar cell 5. Nuclear power plant (e) Dams are constructed for power generation

 Column I Column II 1. Thermal power plant (c) Use coal, petroleum and natural gas to produce thermal electricity 2. Hydro power plant (e) Dams are constructed for power generation 3. Major component of biogas (a) Methane 4. Device which converts solar energy into electricity (d) Solar cell 5. Nuclear power plant (b) Nuclear fission

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### Browse & Download CBSE Books For Class 10 - All Subjects

The GSEB Books for class 10 are designed as per the syllabus followed Gujarat Secondary and Higher Secondary Education Board provides key detailed, and a through solutions to all the questions relating to the GSEB textbooks.

The purpose is to provide help to the students with their homework, preparing for the examinations and personal learning. These books are very helpful for the preparation of examination.

For more details about the GSEB books for Class 10, you can access the PDF which is as in the above given links for the same.