Mark (✓) the correct answer: Rayon | Class 8 Science Chapter Synthetic Fibres and Plastics, Synthetic Fibres and Plastics NCERT Solutions

Describe with the help of a diagram an instrument which can be used to detect a charged body.

Sketch larynx and explain its function in your own words.

Arrange the following boxes in proper order to make a flow chart of sugarcane crop production.

Make a labelled diagram of a candle flame.

What is metamorphosis? Give examples.

The following Table shows the total power shortage in India from 1991– 1997. Show the data in the form of a graph. Plot shortage percentage for the years on the Y-axis and the year on the X-axis.

Make sketches of animal and plant cells. State three differences between them.

Describe the construction of a kaleidoscope.

What is a constellation? Name any two constellations.

Complete the crossword with the help of clues given below:
Across
1. This is necessary for photosynthesis.
3. Term for component present in the cytoplasm.
6. The living substance in the cell.
8. Units of inheritance present on the chromosomes.

Down
1. Green plastids.
2. Formed by collection of tissues.
4. It separates the contents of the cell from the surrounding medium.
5. Empty structure in the cytoplasm.
7. A group of cells.

Explain the differences between pure air and polluted air.

A child staying in a coastal region tests the drinking water and also the seawater with his tester. He finds that the compass needle deflects more in the case of seawater. Can you explain the reason?

Give examples to show that friction is both a friend and a foe.

Which of the following voices is likely to have minimum frequency?
(a) Baby girl (b) Baby boy
(c) A man (d) A woman

When the free ends of a tester are dipped into a solution, the magnetic needle shows deflection. Can you explain the reason?

How are babies produced through IVF technique? What are such babies called?

What are antibiotics? What precautions must be taken while taking antibiotics?

Phases of the moon occur because

(a) we can see only that part of the moon which reflects light towards us.
(b) our distance from the moon keeps changing.
(c) the shadow of the Earth covers only a part of moon’s surface.
(d) the thickness of the moon’s atmosphere is not constant.

Explain why sportsmen use shoes with spikes.

A pendulum oscillates 40 times in 4 seconds. Find its time period and frequency.