Secondary School (English Medium) (5 to 8) इयत्ता ७ - CBSE Question Bank Solutions for Science

State whether the following statement is true or false. Correct the false statement.

Calamine can be used to treat ant’s sting.

You are provided with three test tubes A, B and C as shown in figure with different liquids. What will you observe when you put

1. a piece of blue litmus paper in each test tube.
2. a piece of red litmus paper in each test tube.
3. a few drops of phenolphthalein solution to each test tube.
   

Explain two neutralisation reactions related to daily life situation.

Give one example of an animal that can live both in water and on land.

Name two animals each that live in Polar region and Tropical rain forests.

Differentiate between:

Climates of polar region and tropical rain forest

The main cause of wind movement is uneven ______ on the earth.

A flag mounted on a flag post near the sea coast flutters in the direction of sea. At what time of the day does this happen – at midnight or in the afternoon?

Which of the following situations – ‘A’ or ‘B’ – is advantageous for absorption of water and minerals? Why?

Situation ‘A’: Growth and branching of roots in the C-horizon.

Situation ‘B’: Growth and branching of roots in A and B-horizons.

Continuously water-logged soils are disadvantageous for plant growth. Why?

In towns and cities, generally, the bore wells have to be dug very deep to get water as compared to bore wells dug in villages. Give suitable reasons.

When a switch is in OFF position,

1. circuit starting from the positive terminal of the cell stops at the switch.
2. circuit is open.
3. no current flows through it.
4. current flows after some time. 

Choose the combination of correct answer from the following.

An electric cell produces electricity from the ______ ______ in it.

Unscramble the following words:

SFEU

Can we use the same fuse in a geyser and a television set? Explain.

Name two electric devices for each where

1. heating effect of current is used and
2. magnetic effect of current is used.

Your teacher has shown you the following activity.

Activity: Teacher has wound a long insulated piece of wire around an iron nail in the form of a coil. Free ends of the wire are connected to a cell through a switch as shown in the following figure. The current is switched on and some pins are placed near the ends of the nail.

Write down any three questions that come to your mind about this activity.

Paheli took a wire of length 10 cm. Boojho took a wire of 5 cm of the same material and thickness. Both of them connected the wires as shown in the circuit given in the following figure. The current flowing in both the circuits is the same.

1. Will the heat produced in both cases be equal? Explain.
2. Will the heat produced be the same if the wires taken by them are of equal lengths but of different thickness? Explain.

If an object is placed at a distance of 0.5 m in front of a plane mirror, the distance between the object and the image formed by the mirror will be

A rainbow can be seen in the sky