Waec Physics 1999 Past Questions and Answers

Question 21:

• WAEC 1999

Calculate the power rating of an immersion heater used for 10 minutes to increase the temperature of 10kg of water by 15K. (Specific heat capacity of water = 4200 J l-1K^-1)

A. 1,050W
B. 16,800W
C. 18,060W
D. 20,160W

Question 22:

• WAEC 1999

A ray of light is incident on 'a plane mirror at an angle of 20^o. This mirror is rotated through, twice this angle, In this new position the angle between the incident ray and the reflected ray is

A. 20^o
B. 40^o
C. 80^o
D. 120^o.

Question 23:

• WAEC 1999

The air column in a resonance tube is set into resonance by a vibrating tuning fork. The resultant waves in the air column will be

A. Mechanical and transverse
B. Progressive and longitudinal
C. Stationary and transverse
D. Stationary and longitudinal.

Question 24:

• WAEC 1999

The image of an object is located 6cm behind a convex mirror. If its magnification is 0.6, calculate the focal length of the mirror

A. 3.75cm
B. 6.60cm
C. 10.00cm
D. 15.00cm

Question 25:

• WAEC 1999

The refractive index of glass for yellow light is greater than that for red light because yellow light

A. Has a greater amplitude than red light
B. Is more intense than red light
C. Travels more slowly than red light
D. Deviates less than red light