Physics Past Questions And Answers
A house has ten 40W and five 100W bulbs. How much will it cost the owner of the house to keep them lit for 10 hours if the cost of a unit is 5N?
- A. N90
- B. N50
- C. N45
- D. N5
A gas at a pressure of 105Nm-2 expands from 0.6m-3 to 1.2m3 at constant temperature, the work done is
- A. 7.0 x 106J
- B. 6.0 x 10 6J
- C. 6.0 x 10 5J
- D. 6.0 x 10 4J
A dam is able to hold a large quantity of water because its wall is
- A. thickest at the top
- B. thickest at the middle
- C. thickest at the bottom
- D. of the same thickness throughout
In which of the following piece of apparatus is the radius of curvature equal to twice the focal length?
- A. converging lens
- B. diverging lens
- C. converging mirror
- D. parabolic mirror
(a)(i) State two advantages of alcohol over mercury as a thermometric liquid.
(ii) When the bulb of a thermometer is placed in a beaker of hot water, the level of the mercury first falls and then rises gradually. Explain this observation.
(b) List two factors, other than temperature, that affect the rate of evaporation of a liquid.
(b) A block of lead of mass 100 kg in a crucible and at a temperature of 40 °C was placed in an electric furnace rated 10 kW. If the melting point of lead is 320 °C, calculate the:
(i) quantity of heat required to heat the lead to its melting point;
(ii) additional heat energy required to melt the lead;
(iii) time taken to supply this additional energy. (Specific heat capacity of lead = 120 Jkg\(^{-1}\) K\(^{-1}\) (Specific Idtent heat of fusion lead = 2.5 x 10\(^{4} JK^{-1}\))
(d) State two precautions necessary in an experiment to determine the specific latent heat of vaporization of water.
View Discussion (0)WAEC 2011 THEORYIn the diagram illustrated a block of mass M is at rest on a plane inclined at an angle \(\theta\) to the horizontal. As \(\theta\) increases, the velocity ratio of the plane
- A. increases
- B. decreases
- C. remain the same
- D. decreases and later increases
Which of the following factors does not increase the rate of evaporation of water in a lake?
- A. Increase in the pressure of the atmosphere
- B. Rise in temperature
- C. Increase in the surface area of the lake
- D. Increase in the speed of the wind
A ray of light is incident on mirror m1 and after reflection is incident on mirror m2 as shown in the diagram, calculate the angle of reflection of the ray at mirror m2
- A. 120°
- B. 90°
- C. 60°
- D. 30°
What is the cost of running seven 40 W lamps and five 80 W lamps for 12 hours of the electrical energy cost N7.00kWh?
- A. N80.00
- B. N45.36
- C. N65.00
- D. N57.12
(a) Using the kinetic theory of matter, explain why;
(i) Evaporation causes cooling
(ii) Boiling water changes to steam without any change in temperature, although heat is being supplied to the water.
(b) (i) State Boyle's law.
(ii) With the aid of a labelled diagram, describe an experiment to illustrate the relationship between the volume and pressure of a given mass of gas at constant temperature. (iii) State two precautions necessary to obtain accurate results.
View Discussion (0)WAEC 2003 THEORY
.jpg)