List of top Science Questions

An inflated balloon was pressed against a wall after it has been rubbed with a piece of synthetic cloth. It was found that the balloon sticks to the wall. What force might be responsible for the attraction between the balloon and the wall?

Give two examples of each.
1. Kharif crop
2. Rabi crop

Show with the help of a sketch that plants are the ultimate source of food.

Why is it advised to tie any luggage kept on the roof of a bus with a rope?

Four children were asked to arrange forces due to rolling, static and sliding frictions in a decreasing order. Their arrangements are given below. Choose the correct arrangement.

One-half of a convex lens is covered with a black paper. Will this lens produce a complete image of the object? Verify your answer experimentally. Explain your observations.

You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.

Why is a normal eye not able to see clearly the objects placed closer than 25 cm?

Which type of cell division is required for growth and repair of body and which type is involved in formation of gametes?

Why is ice at 273K more effective in cooling than water at the same temperature?

Look at the activities listed below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
• Suma is swimming in a pond.
• A donkey is carrying a load on its back.
• A wind-mill is lifting water from a well.
• A green plant is carrying out photosynthesis.
• An engine is pulling a train.
• Food grains are getting dried in the sun.
• A sailboat is moving due to wind energy.

The weather department has predicted that a thunderstorm is likely to occur on a certain day. Suppose you have to go out on that day. Would you carry an umbrella? Explain.

Prepare a list of objects around you that are electroplated.

What is the importance of universal law of gravitation?

What are the differences between the transport of materials in xylem and phloem?

Two children are at opposite ends of an aluminium rod. One strikes the end of the rod with a stone. Find the ratio of times taken by the sound wave in air and in aluminium to reach the second child.

An object of mass \(40\) \(kg\) is raised to a height of \(5\) \(m\) above the ground. What is its potential energy? If the object is allowed to fall, find its kinetic energy when it is half-way down.

Differentiate between regular and diffused reflection. Does diffused reflection mean the failure of the laws of reflection?

An object of mass, m is moving with a constant velocity, v. How much work should be done on the object in order to bring the object to rest?

An electric bulb is rated 220 V and 100 W. When it is operated on 110 V, the power consumed will be –

Differentiate between metal and non-metal on the basis of their chemical properties.

Describe characteristics and uses of coke.

Which of the following lenses would you prefer to use while reading small letters found in a dictionary?