Question

Q.7 Answer in one or two sentences.
a) What happens during storm?
b) What causes seasons on the earth?
c) What are constellations?
d) How much of water is present on the earth?
e) What is sound?
Q.8 Draw label and colour the following diagrams.
a) Two natural luminous objects
b) Two man-made luminous objects
c) One non-luminous object​

Answer 1

Answer:

NCERT for Some Natural Phenomena

Select the correct option in questions 1 and 2.

Q.1. Which of the following cannot be charged easily by friction?

(a) A plastic scale

(b) A copper rod

(c) A inflated balloon

(d) A woollen cloth.

Ans. (b) A copper rod.

Q.2. When a glass rod is rubbed with a piece of silk cloth the rod:

(a) and the cloth both acquire positive charge.

(b) becomes positively charged while the cloth has a negative charge.

(c) and the cloth both acquire negative charge.

(d) becomes negatively charged while the cloth has a positive charge.

Ans. (b) becomes positively charged while the cloth has.a negative charge.

Q.3. Write ‘T’ against true and ‘F’ against false in the following statements:

(a) Like charges attract each other.

(b) A charged glass rod attracts a charged plastic straw.

(c) Lightning conductor cannot protect a building from lightning.

(d) Earthquakes can be predicted in advance,

Ans. (a) False (b) True (c) False (d) False

Q.4. Sommetim.esa crackling sound is heard while taking off sweater during winters. Explain.

Ans. The electric discharge takes place between body and sweater. At the time of electric discharge some energy is released. In this case erergy is released in the form of cracking sound.

Q.5. Explain why a charged body loses its charge if we touch it with our hand.

Ans. When we touch a charged bo