Waec Physics 1991 Past Questions and Answers

Question 51:

• WAEC 1991

An induction coil is generally used to

A. Rectify an alternating current
B. Produce a large input voltage
C. Smoothen a pulsating direct current
D. Modulate an incoming signal
E. Produce a large output voltage

Question 52:

• WAEC 1991

The unit of stress is

A. Nm
B. N
C. Nm^-2
D. Nm²
E. Nm¹

Question 53:

• WAEC 1991

Which of the following statements above viscosity are correct? when a ball falls through a viscous liquid i. viscosity opposes the gravitational force on the ball. ii. viscosity opposes the upthrust on the ball. iii. viscosity is in the same direction as the upthrust on the ball. iv. as the ball falls faster the more viscous the liquid is

A. I and iii only
B. I and ii only
C. Ii and iv only
D. Iii and iv only
E. I, ii and iv only

Question 54:

• WAEC 1991

Which of the following statements is not correct? Isotopes of an element have

A. The same number of electric charges on the nucleus
B. The same chemical properties
C. Different nucleon numbers
D. Different proton numbers
E. Different atomic masses

Question 55:

• WAEC 1991

plane as 63cm of HG while a ground observer records a reading of 75cm of Hg with his barometer. assuming that the density of air is constant, calculate the height of the plane above the ground. (Take the relative densities of air and mecury as 0.00136 and 13.6 respectively

A. 120m
B. 138m
C. 1200m
D. 274m
E. 120,000m