Physics questions and answers

Physics Questions and Answers

If you want to learn more about the nature and properties of matter and energy or you're simply preparing for a Physics exam, these Physics past questions and answers are ideal for you.

646.

A particle of mass M initially at rest splits into two. If one of the particles of mass M1 moves with velocity V1 , the second particle moves with velocity

A.

\(\frac{M1V1}{M-M1}\)

B.

\(\frac{M1V1}{M1-M}\)

C.

\(\frac{M1V1}{M}\)

D.

\(\frac{MV}{M-M1}\)

Correct answer is B

No explanation has been provided for this answer.

647.

The friction which exist between two layers of liquid in relative motion is called

A.

Capillary

B.

Surface

C.

Viscosity

D.

Cohesion

Correct answer is C

Viscosity, resistance of a fluid (liquid or gas) to a change in shape, or movement of neighboring portions relative to one another. Viscosity denotes opposition to flow. The reciprocal of the viscosity is called the fluidity, a measure of the ease of flow. Molasses, for example, has a greater viscosity than water. Because part of a fluid that is forced to move carries along to some extent adjacent parts, viscosity may be thought of as internal friction between the molecules; such friction opposes the development of velocity differences within a fluid. Viscosity is a major factor in determining the forces that must be overcome when fluids are used in lubrication and transported in pipelines. It controls the liquid flow in such processes as spraying, injection molding, and surface coating.

648.

Which of the following phenomena cannot be explained by the molecular theory of matter?

A.

Conduction

B.

Convection

C.

Expansion

D.

Radiation

Correct answer is D

Conduction: the flow of internal energy from a region of higher temperature to lower temperature
Convection: heat transfer due to bulk movement of molecules within fluids
Expansion: the action of becoming larger or more extensive

649.

A room is heated by means of a charcoal fire, an occupants of the room standing away from the fire is warmed mainly by

A.

Convection

B.

Radiation

C.

Conduction

D.

Reflection

Correct answer is B

Radiation refers to the transmission of energy as electromagnetic radiation from its emission at a heated surface to its absorption on another surface, a process requiring no medium to convey the energy.
Conduction is the transferring of heat by direct contact.
Convection is transferring heat through the motions of fluids (gases and liquids).

650.

Which of the following is not a product of nuclear fusion?

A.

X – ray

B.

Y –ray

C.

α – particles

D.

neutron

Correct answer is A

Y – Ray is a penetrating electro-magnetic radiation.
α – particle is produced in the process of alpha decay.
Neutron is a sub-atomic particle.