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Q1. Name 6 Indian Scientists who have made significant contributions in Physics.

Solution

The six Indian scientists are C.V. Raman, S.N Bose, J.C. Bose, S. Chandrasekhar, Meghnad Saha and Homi Bhabha.

Q2. What is physics?

Solution

Physics is a branch of science dealing with the nature and natural phenomenon.

Q3. Give the properties of electromagnetic force.

Solution

The properties of electromagnetic force are as follows: 1) It obeys the inverse square law. 2) It may be attractive or repulsive in nature. 3) It is a long range force. 4) The photon is the field particle of electromagnetic force. 5) It is about 10³⁶ times stronger than the gravitational force. 6) It is a central force as well as a conservative force.

Q4. Give the properties of gravitational force.

Solution

The gravitational force has the following properties: 1) It obeys the inverse square law. 2) It is always attractive in nature. 3) It is a long range force. It extends up to infinity. 4) The graviton is the field particle of gravitational force. 5) It is the weakest force operating in nature. 6) It is a central force and hence a conservative force.

Q5. State the law of conservation of angular momentum.

Solution

The law of conservation of angular momentum states that, "if no external torque acts on a system, then the total angular momentum of the system always remains constant".

Q6. What is the difference between science and technology?

Solution

Science is the study of laws of nature while technology is the application of these laws in practical situations.

Q7. Give examples of conservation of linear momentum from daily life.

Solution

1) When a bullet is fired from a gun, the recoil of the gun can be explained on the basis of the law of conservation of linear momentum. 2) When a heavy nucleus at rest disintegrates into two smaller nuclei, the products move in opposite directions, obeying the law of conservation of linear momentum. 3) The motion of rockets is obeyed by the law of conservation of linear momentum.

Q8. Who discovered the law of gravitation?

Solution

Sir Isaac Newton discovered the law of gravitation.

Q9. Give the properties of nuclear force.

Solution

The nuclear force has the following properties: 1) The strong nuclear force binds protons and neutrons in a nucleus. The weak nuclear force appears only in certain nuclear processes such as beta decay. 2) Strong nuclear force is the strongest force in nature. It is about 100 times stronger than electromagnetic force. Weak nuclear force is stronger than the gravitational force but weaker than the electromagnetic or strong nuclear force. 3) It is a short-range force and is operative only over the size of nucleus. 4) Strong nuclear force is responsible for the stability of nuclei.

Q10. State the law of conservation of energy.

Solution

The law of conservation of energy states that, "energy can neither be created nor can be destroyed, however it may be converted from one form to another".