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

Two methods by which rusting of iron can be prevented are ______ and ______.

Explain how painting of an iron gate prevents it from rusting.

Explain why rusting of iron objects is faster in coastal areas than in deserts.

The rear view mirror of a car is a plane mirror. A driver is reversing his car at a speed of 2 m/s. The driver sees in his rear view mirror the image of truck parked behind his car. The speed at which the image of the truck appears to approach the driver will be ______.

Dried ______ is used as manure.

Drains get blocked by ______ and ______.

Describe the steps involved in getting clarified water from wastewater.

Explain how sludge is treated.

Name two chemicals used to disinfect water.

Explain the function of bar screens in a wastewater treatment plant.

Study the following statements about ozone:

1. It is essential for breathing of living organisms.
2. It is used to disinfect water.
3. It absorbs ultraviolet rays.
4. Its proportion in air is about 3%.

Which of these statements are correct?

Teeth are rooted in separate ______ in between the ______.

Label the below given Figure as directed below in (i) to (iv) and give the name of each type of teeth.

1. The cutting and biting teeth as ‘A’
2. The piercing and tearing teeth as ‘B’
3. The grinding and chewing teeth as ‘C’
4. The grinding teeth are present only in adults as ‘D’

Open your mouth, look into a mirror and try to count the different types of teeth in your mouth. Compare them with Figure on page 13 of your NCERT textbook.

Record your observations in the table below:

1. Did you observe any difference in the number of teeth? If yes, could you identify which type of teeth showed the difference?
2. Compare the number and type of teeth in an adult (say your parents or cousins who have reached the age of 25-30 or more). Note your observation.

Which of the following is not a type of silk?

Silk fibre is obtained from ______.

The general process that takes place at a sheep shearing shed is ______.

The term sericulture is used for ______.

Reeling of silk is ______.

State whether the following statement is True or False. If false, correct them.

Silkworms are caterpillars of silk moth.