Waec Physics 1989 Past Questions and Answers

Question 16:

• WAEC 1989

Which of the following substance is not a good conductor of electricity?

A. Human body
B. Glass
C. Aluminium
D. Earth
E. Copper

Question 17:

• WAEC 1989

Calculate the heat energy required to vapourize 50g of water initially at 80^oC if the specific heat capacity of water is 4.2Jg^-1K (specific latent heat of vapourization of water is 2260Jg^-1).

A. 533000J
B. 230000J
C. 117200J
D. 113000J
E. 4200J

Question 18:

• WAEC 1989

A block of ice at its melting point is left on a table in the atmosphere and observed to melt gradually. Which of the following statements is true about the melting process?

A. The reaction force of the table on the ice breaks the ice into water molecules
B. Heat extracted from the ice block makes the ice block cold
C. The ice block absorbs heat from the atmosphere and its temperature rises
D. The atmosphere absorbs heat from the ice block and its temperature falls
E. The ice block absorbs heat from the atmosphere and its temperature remains constant as it melts

Question 19:

• WAEC 1989

All the heat generated by a current of 2A passing through a resistor of 6Ω for 2.5s is used to evaporate 5 g of a liquid at its boiling point. What is the specific latent heat of the liquid?

A. 60 Jg^-1
B. 120 Jg^-1
C. 300 Jg^-1
D. 360 Jg^-1
E. 1500 Jg^-1

Question 20:

• WAEC 1989

Which of the following instruments can be used to compare the relative magnitudes of charges on two given bodies?

A. The electrophorous
B. Ebonite rod
C. Proof plane
D. Gold leaf electroscope
E. Capacitor