Physics 2020 Waec Past Questions and Answers

Question 36 :

• WAEC 2020

Which of the following statements correctly explains why a total solar eclipse would be seen by people on only a small portion of the earth's surface? The

A. Moon is larger in diameter than the earth
B. Eath is larger in diameter than the sun
C. Earth revolves around the sun
D. Earth is larger in diameter than the moon.

Question 37 :

• WAEC 2020

Water waves have a wavelength of 3.6cm and speed of 18cms\(^{-1 }\) in deep water. If the waves enter shallow water with wavelength of 2.0cm, calculate the speed of the waves in the shallow water.

A. 0.4cms\(^{-1}\)
B. 2.5cms\(^{-1}\)
C. 10.0cms\(^{-1}\)
D. 10.8cms\(^{-1}\)

Question 38 :

• WAEC 2020

An a.c. generator can be converted to a d.c. electric motor by replacing the

A. Slip rings with a split ring and connecting a battery
B. Split ring with slip rings and connecting a battery
C. A.c. with d.c. source and connecting slip rings
D. A.c. with d.c. source and connecting split rings

Question 39 :

• WAEC 2020

A ray of light travels obliquely from a less dense medium to a denser medium. Which of the following statements is true about the light?

A. The wavelength of the light increases in the second medium
B. The speed of the light increases in the second medium
C. The light refracts towards the normal
D. There Is a change in the frequency of the light

Question 40 :

• WAEC 2020

An electron of mass 9.1x 10\(^{31}\) kg is travelling at a speed of 2.0 x 10\(^6\)ms\(^{-1}\). Calculate the associate wavelength of the electron. [h = 6.6. x 10\(^{34}\) Js]

A. 3.63 x10\(^{10}\) m
B. 3.63 x 10\(^{-8}\) m
C. 3.63 x 10\(^{-7}\) m
D. 6.89 x 10\(^{-4}\) m