physics

Which of the following types of waves needs a medium for propagation?

A. sound waves B. light waves C. radio waves D. x - rays Correct Answer: Option A - sound waves…

5 years ago

Which of the following could be effectively used to reduce friction?

A. kerosene B. grease C. water D. petrol Correct Answer: Option B - grease Explanation grease is more viscous than…

5 years ago

In which of the statement below will pressure be dependent?

I. Density of the liquid. II. Depth below the surface of the liquid. III. Surface area of the liquid. A.…

5 years ago

A machine is used to lift a load of 20 N through a height of 10m. if the efficiency of the machine is 40%; how much work is done?

A. 80 J B. 500 J C. 300 J D. 120 J Correct Answer: Option B - 500 J Explanation…

5 years ago

A block of aluminum is heated electrically by a 30w heater if the temperature rises by 10°c in 5 minutes; the heat capacity of the aluminum is?

A. 900 JK−¹ B. 90 JK−¹ C. 100 JK−¹ D. 200 JK−¹ Correct Answer: Option A - 900 JK−¹ Explanation…

5 years ago

The phenomenon that shows that increase in pressure lowers the melting point can be observed in

A. sublimation B. condensation C. coagulation D. regelation Correct Answer: Option D - regelation Explanation Regelation means refreezing a phenomenon…

5 years ago

A cannon is fired from town X; after how long is the sound heard at a town Y 4.95km away? [velocity of sound in the air = 330 ms−¹1]

A. 30s B. 10s C. 10s D. 15s Correct Answer: Option A - 30s Explanation V = (2X)/t 330 =…

5 years ago

The ground is always cold at night because the?

A. atmosphere absorbs the sun's energy at night B. earth radiates heat to the atmosphere at night C. sun no…

5 years ago

A perfect emitter or absorber of radiant energy is a?

A. conductor B. black body C. white body D. red body Correct Answer: Option B - black body Explanation Dull,…

5 years ago

From the statement below; the qualities of a good thermometer are?

I. High thermal capacity. II. High sensitivity. III.Easy readability. IV. Accuracy over a wide range of temperature A. I and…

5 years ago