Question

Q.4: Answer the following in detail:
1. Explain: a) Gravitational force b) Atmospheric pressure
2. Discuss the process of Electroplating with the help of a diagram.
3. We hear sound through our ears. Elaborate.
4. What is the difference between noise and music? List few measures to limit noise pollution.
5. Friction is a necessary evil. Explain?
6. Write down ways of minimising and maximising friction..

Answer 1

gravitational force means in Hindi that gurutvakarshan

Answer 2

Answer:

1) (a) Gravity, also called gravitation, in mechanics, the universal force of attraction acting between all matter. On Earth all bodies have a weight, or downward force of gravity, proportional to their mass, which Earth's mass exerts on them. Gravity is measured by the acceleration that it gives to freely falling objects.

(b) the pressure exerted by the weight of the atmosphere, which at sea level has a mean value of 101,325 pascals (roughly 14.6959 pounds per square inch).

3) The sound waves are gathered by the outer ear and sent down the ear canal to the eardrum. The sound waves cause the eardrum to vibrate, which sets the three tiny bones in the middle ear into motion. The motion of the bones causes the fluid in the inner ear or cochlea to move.

4) The minimum sound of 50 db which we can listen pleasantly is called sound. The sound which is above 95 db and also which causes irritation to listen is called noise pollution.

5) Frictional force causes a lot of losses in general upkeep and wear and tear of machinery. Hence it is considered as a evil. But almost all crucial tasks cannot be carried out without the presence of friction. Hence it is considered as a necessary evil .

6) Here is your perfect answer!

• To keep surface more and more smooth.
• To reduce friction between two rubbing surfaces, a suitable oil or grease can be used.
• The rolling force of friction is least, so we can used rolling form of motion.

2) In this process, there exists an electrolyte, through which current passes. Two electrodes are inserted in the electrolyte and are connected to the terminals of a battery with a switch in between. The metal to be used for coating is chosen as the anode and the object to be electroplated is chosen as the cathode.

Top of the image is second answer