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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.

2,936.

A piece of wood floats inside water at room temperature with a fraction of it above the liquid surface. As the temperature of the water is raised, the part of the wood above the liquid will

A.

decrease because the density of water decreases with temperature

B.

increase because the density of water decreases with temperature

C.

decreases because the density of water increases with water temperature

D.

increase because the density of water increases with temperature

Correct answer is A

No explanation has been provided for this answer.

2,937.

A rectangular metal block of volume 10-6m3 at 273k is heated to 573k. If its coefficient of linear expansion is 1.2 x 10-5k-1, the percentage change of it volume is

A.

1.5%

B.

1.1%

C.

0.4%

D.

0.1%

Correct answer is B

Y = ΔVV×Δθ

3 x 10-5 x 1.2 = Δ V106× (573273)

ΔV = 1080 x 10-11m3

%ΔV = 1080× 10106 x 100

= 1.08%

= 1.1%

2,938.

Temperature is the measure of the

A.

quantity of heat transferred into the molecules of an object

B.

mean kinetic energy of the molecules of the object

C.

kinetic energy of any individual molecule of the substance

D.

amount of work done by the molecules of the object

Correct answer is B

No explanation has been provided for this answer.

2,939.

The volume of an air bubble increases from the bottom to the top of a lake at constant temperature because

A.

atmospheric pressure acts on the surface of the lake

B.

pressure increases with depth

C.

density remains constant with pressure

D.

the bubble experiences an upthrust

Correct answer is B

No explanation has been provided for this answer.

2,940.

A hydraulic press has a large circular piston of radius 0.8m and a circular plunger of radius 0.2m. A force of 500N is exerted by the plunger. Find the force exerted on the piston

A.

8000N

B.

4000N

C.

2000N

D.

31N

Correct answer is A

Pressure on piston = pressure on the plunger

500π × 0.2× 0.2 = Fπ × 0.8× 0.8

F = 8000N