Question

GOLDEN SCIENCE-VII
(1) What is the speed of sound in air?
g Name two metal objects which have a coating of another metal.
(h) What are the two kinds of electric charges?
(i) State one use of kaleidoscope.
5) Name a star having a system of planets with life on one of its planets.
Short Answer Type Questions:
(2 X 9 = 18)
a) State two ways in which the body shape of the boys changes during puberty,
3) What is meant by lubrication? Why is it important?
-) What is the time period of a pendulum which is vibrating with a frequency of
10 hertz?
) Why is it dangerous to touch a working electrical appliance with wet hands?
What will you observe when the metal top of an electroscope is touched with a
plastic comb rubbed in dry hair? Give reason for your answer.
What is Periscope? How many mirrors are there in a Periscope.​

Answer 1

the two types of electric charge are positive and negative charge