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Gurmit wanted to perform Activity 16.8 using a laser torch. Her teacher advised her not to do so. Can you explain the basis of the teacher’s advise?

Laser torch has laser light. Laser light has very high intensity and hence it is harmful for the human eyes.... View Article

Which of the non-living things listed below, were once part of a living thing? Butter, Leather, Soil, Wool, Electric bulb, Cooking oil, Salt, Apple, Rubber

The non-living things which were once a part of living things are butter, leather, wool, cooking oil, apple, and rubber.... View Article

Show the shape of the distance-time graph for the motion in the following cases: (i) A car moving with a constant speed. (ii) A car parked on a side road.

(i) A car moving with a constant speed covers equal distance in equal intervals of time. It will be a... View Article

Water absorption through roots can be increased by keeping the plants (i) in the shade (ii) in dim light (iii) under the fan (iv) covered with a polythene bag

Water absorption through roots can be increased by keeping the plants under the fan Explanation Water absorption through the roots... View Article

An electrician is carrying out some repairs in your house. He wants to replace a fuse by a piece of wire. Would you agree? Give reasons for your response.

No, the electrician should not be allowed to replace the fuse in the house with a piece of wire. This... View Article

Choose the correct option from the following: Plants take carbon dioxide from the atmosphere mainly through their: (i) roots (ii) stem (iii) flowers (iv) leaves

(i) Carbon dioxide is released during photosynthesis. (False) During the process of photosynthesis, cells use carbon dioxide and energy from... View Article

Why is the distance between stars expressed in light years? What do you understand by the statement that a star is eight light-years away from the Earth?

Stars are millions of kilometres away from the earth & giving their distances in the kilometres unit becomes very inconvenient.... View Article

A rocket has been fired upwards to launch a satellite in its orbit. Name the two forces acting on the rocket immediately after leaving the launching pad.

Two forces acting on the rocket immediately after leaving the launching pad are: Thrust provided by burning fuel in an... View Article

In addition to the rock particles, the soil contains (i) air and water (ii) water and plants (iii) minerals, organic matter, air and water (iv) water, air and plants

(iii) minerals, organic matter, air and water Explanation All soil is made up of inorganic mineral particles, organic matter (including... View Article

Mark ‘T’ if the statement is true and ‘F’ if it is false: When the electric current through the fuse exceeds a certain limit, the fuse wire melts and breaks. (T/F)

When the electric current through the fuse exceeds a certain limit, the fuse wire melts and breaks- True Explanation When... View Article

The handles of the tools like screwdrivers and pliers used by electricians for repair work usually have plastic or rubber covers on them. Can you explain why?

Plastic and rubber both are bad conductors of electricity. So, they do not allow current to pass through them. The... View Article

While measuring the length of a knitting needle, the reading of the scale at one end is 3.0 cm and at the other end is 33.1 cm. What is the length of the needle?

The length of the knitting needle is the difference between two readings. Thus, length of knitting needle = 33.1− 3.0... View Article

Discuss the effects of deforestation on the following. (a) Wild animals (b) Environment (c) Villages (Rural areas) (d) Cities (Urban areas) (e) Earth (f) The next generation

(a) Wild animals: Due to the deforestation natural habitat of the animals are destroyed. Without the natural habitat the animals... View Article

The radius of Jupiter is 11 times the radius of the Earth. Calculate the ratio of the volumes of Jupiter and the Earth. How many Earths can Jupiter accommodate?

The volume of sphere = 4/3 ℼr3 Let the radius of the earth be ‘r’ The radius of Jupiter =... View Article

You are a member of the municipal body of your town. Make a list of measures that would help your town to ensure the supply of clean water to all its residents.

We can take the following measures: Water should be treated properly before use to make it free from harmful germs,... View Article

When milk, cooled after boiling, is poured onto a piece of cloth the cream (malai) is left behind on it. This process of separating cream from milk is an example of ___________.

When milk, cooled after boiling, is poured onto a piece of cloth, the cream (malai) is left behind on it.... View Article

Mark ‘T’ if the statement is true and ‘F’ if it is false: The freshwater stored in the ground is much more than that present in the rivers and lakes of the world. (T/F)

True. The freshwater stored in the ground is much more than that present in the rivers and lakes of the... View Article

Salma takes 15 minutes from her house to reach her school on a bicycle. If the bicycle has a speed of 2 m/s, calculate the distance between her house and the school.

Given that, Speed of the bicycle = 2m/s Time taken to reach school = 15 minutes = 15 × 60... View Article

Choose the correct option. Reproductive age in women starts when their (i) menstruation starts. (ii) breasts start developing. (iii) body weight increases. (iv) height increases.

(b) Reproductive age in women starts when their menstruation starts. Explanation Menstruation, or period, is normal vaginal bleeding that occurs... View Article

Which one of the following is not responsible for water shortage? (i) Rapid growth of industries (ii) Increasing population (iii) Heavy rainfall (iv) Mismanagement of water resources

Heavy rainfall Water is one of the most valuable resources on Earth. Rainwater fills reservoirs that supply drinking water, provide... View Article

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