Secondary School (English Medium) (5 to 8) Class 7 - CBSE Question Bank Solutions

Grinding of wheat grain changes its size. It is a ____________ change.

Give two examples for the following case:

Physical changes which are reversible

Give two examples for the following case:

Physical changes which are not reversible

If you leave a piece of iron in the open for a few days, it acquires a film of brownish substance, called rust.

Do you think rust is different from iron?

Veins have valves that allow blood to flow only in one direction. Arteries do not have valves. Yet the blood flows in one direction only. Can you explain why?

What is the special feature present in a human heart which does not allow mixing of blood when oxygen-rich and carbon dioxide-rich blood reach the heart?

Name the organ which is located in the chest cavity with its lower tip slightly tilted towards the left.

Name the only artery that carries carbon dioxide-rich blood.

Why is it called an artery if it does not carry oxygen-rich blood?

Paheli noticed water being pulled up by a motor pump to an overhead tank of a five-storeyed building. She wondered how water moves up to great heights in the tall trees standing next to the building. Can you tell me why?

While learning to ride a bicycle Boojho lost his balance and fell. He got bruises on his knees and it started bleeding. However, the bleeding stopped after some time.

1. Why did the bleeding stop?
2. What would be the colour of the wounded area and why?
3. Which type of blood cells are responsible for clotting of blood?

A simple pendulum is oscillating between two points A and B as shown in figure. Is the motion of the bob uniform or non-uniform?

Given below as figure is the distance-time graph of the motion an object.

1. What will be the position of the object at 20s?
2. What will be the distance travelled by the object in 12s?
3. What is the average speed of the object?

Which of the following precautions need not be taken while using electric gadgets/appliances/circuit?

Which property of a conducting wire is utilised in making electric fuse?

Why are compact fluorescent lamps (CFLs) preferred over electric bulbs?

Why is an electric fuse required in all electrical appliances?

Draw the symbols of the following circuit components.

Electric bulb

Which of the following does not show water shortage?

Which of the following does not show water shortage?