Waec Physics 1990 Past Questions and Answers

Question 56:

• WAEC 1990

Water does not drip through an open umbrella of silk material unless the inside of the umbrella is touched. Which of the following phenomena is responsible for this?

A. Surface tension
B. Hydrostatic upthrust
C. Viscosity
D. Diffusion
E. Osmosis

Question 57:

• WAEC 1990

A radioactive substance has a half-life of 20 hours. What fraction of the original radioactive nuclei will remain after 80 hours?

A. 1/32
B. 1/16
C. 1/8
D. 1/4
E. 1/2

Question 58:

• WAEC 1990

A metal is illuminated with a radiation of energy 6.88eV If the kinetic energy of the emitted electrons is 1.5OeV, calculate the work function of the metal.

A. 0.22eV
B. 4.59eV
C. 5.38eV
D. 8.38eV
E. 10.32eV

Question 59:

• WAEC 1990

Viscosity in a liquid does not depend on the

A. Nature of the liquid
B. Relative velocity between the liquid layers
C. Area of the surfaces in contact
D. Temperature of the liquid
E. Normal reaction between the liquid layers

Question 60:

• WAEC 1990

Which of the following is not crystal?

A. Sodium chloride
B. Lead
C. Copper (II) tetraoxosulphate (VI)
D. Glass
E. Germanium