Waec Physics 1998 Past Questions and Answers

Question 56:

• WAEC 1998

The frictional effect between the layers of a moving fluid is called

A. Capillarity
B. Turbulence
C. Diffusion
D. Osmosis
E. Viscosity

Question 57:

• WAEC 1998

Two radioactive elements X and Y have half-lives of 100 and 50 years respectively. Samples of X and Y initially contain equal number of atoms. What is the ratio of the number of the remaining atoms of X to that of Y after 200 years?

A. 4:1
B. 3:1
C. 1:1
D. 1:2
E. 1:4

Question 58:

• WAEC 1998

It is always not possible to determine exactly and simultaneously the position and momentum of a particle. This statement is known as the

A. De broglie's law
B. Heisenberg's uncertainty principle
C. Compton effect
D. Frank-Hertz experimental law
E. Wave particle paradox

Question 59:

• WAEC 1998

(a) Explain the term uniform acceleration
(b)(i) Sketch and describe the velocity-time graph for the motion of a ball from the time it is projected vertically upwards until it returns to the point of projection.
(ii) Neglecting air resistance and using ycur sketch, explain how the acceleration of free fall due to gravity g, and the maximum height attained when the ball is projected vertically upwards can be determined.
(c) A stone is projected vertically upwards with a velocity of 20ms\(^{-1}\). Two seconds later, a second stone is similarly projected with the same velocity. When the two stones meet, the second one is rising at a velocity of 10ms\(^{-1}\). Neglecting air resistance, calculate the:
(i) length of time the second stone is in motion before they meet,
(ii) velocity of the first stone when they meet (Take g as 10ms\(^{-2}\))

Question 60:

• WAEC 1998

(a) Distinguish between heat and temperature.
(b) State two physical properties of substances which may be used to measure temperature.
(c) State two reasons why mercury is preferred to alcohol as a thermometric liquid.
(d)(i) Describe how a mercury-in-glass thermometer is calibrated.
(ii) State two precautions necessary to ensure an accurate result.
(e) Explain how land and sea breezes occur.