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

Which one of the following solutions will not conduct electricity?

Observe the circuit given in the figure.

Boojho set up this circuit for purification of copper. What will be the nature of – (i) plate A (ii) plate B (iii) and the solution.

Explain the process of purification.

Observe the following circuit given in the figure.

Current does not flow in the circuit, if there is a gap between the two wires. Does it indicate that air is a poor conductor of electricity? Does air never conduct electricity? Explain.

Boojho made the circuit as shown in the figure. He wanted to observe what happens when an electric current is passed through water. But he forgot to add a few drops of lemon juice to water. Will it make any difference to his observations? Explain.

Observing that the bulb does not glow in the circuit shown in the following figure A, Boojho changed the circuit as shown in the following figure B. He observed deflection in the magnetic compass.

A	B

1. What does the deflection in magnetic compass indicate?
2. Why did the bulb not glow in the following figure A?
3. What would be the effect of increase in the number of turns in the coil wound around the magnetic compass in the following figure B?
4. What will be observed if the number of cells are increased in the circuit shown in the following figure B?

Part of the eye which controls the light entering is called

An astronaut standing on the surface of the moon throws a ball upwards. The ball would

The first of a month is the new moon day. On fifteenth of the same month, which of the following figures would represent the phase of the moon?

John saw full moon on a particular day. After how many days will he be able to see the full moon again?

Why does the moon change its shape daily?

Paheli saw the moon through a glass window at 8:00 pm. She marked the position of the moon on the glass pane. She got up at 4 am in the morning. Will the moon be visible at the same position?

Explain why we always see the same side of moon.

Look at the figure carefully and answer the following question:

1. In which part of the sky would you see the full moon in the evening?
2. In which part of the sky would you see the crescent moon in the evening?

Match the following:

Write a paragraph in your own words of the following.

Preparation of soil

Yeast is used in the production of ______.

The following is an antibiotic.

The bread or idli dough rises because of ______.

The process of conversion of sugar into alcohol is called ___________.

What are antibiotics?