Physics 1998 Waec Past Questions and Answers

Question 21 :

• WAEC 1998

Dry oxygen is trapped by a pellet of mercury in a uniform capillary tube which is sealed at one end. The length of the column of oxygen at 27^oC is 50cm. if the pressure of the oxygen is constant, at what temperature will the length be 60cm?

A. 360.0^oC
B. 240.6^oC
C. 237.0^oC
D. 87.0^oC
E. 36^oC

Question 22 :

• WAEC 1998

A waterfall is 1.260m high. Calculate the change in temperature of a quantity of water that falls from the top to the bottom of the waterfall. (Neglect heat losses to the surroundings, take g as 10m^-2 and specific heat capacity of water as 4200Jkg^-1K^-1)

A. 0.3^oC
B. 3.0^oC
C. 33.3^oC
D. 42.0^oC
E. 100.0^oC

Question 23 :

• WAEC 1998

A piece of metal is heated until it becomes red-hot, it is then quickly transferred into a beaker containing boiling water. What effect will this have on the boiling water?

A. The boiling water rises slightly
B. The boiling point rises sharply
C. The rate of vaporisation of the boiling water increases
D. The boiling point first rises and then falls
E. Neither the boiling point nor the rate of vaporisation increases

Question 24 :

• WAEC 1998

A 90-W immersion heater is used to supply energy for five minutes. The energy supplied is used to completely melt 180g of a solid at is melting point. Neglecting energy losses to the surroundings, calculate the specific latent heat of fusion of the solid

A. 0.5Jg^-1
B. 2.5Jg^-1
C. 15.0Jg^-1
D. 450.0Jg^-1
E. 150Jg^-1

Question 25 :

• WAEC 1998

If an ebonite rod is rubbed with fur

A. Both the ebonite rod and the fur will be negatively charged
B. The ebonite rod will be positively charged while the fur will have no charge
C. There will be electron transfer only if the ebonite rod is earthed
D. The ebonite rod will be negatively charged while the fur will be positively charged
E. The ebonite rod will be positively charged while the fur will be negatively charged