Physics 2021 Waec Past Questions and Answers

Question 16 :

• WAEC 2021

The components of vectors Q and R are (-3.0, 5.5) and (9.2, 4.4) respectively. Determine the components of Q + R.

A. (3.7, 7.4)
B. (6.2, 9.9)
C. (2.5, -4 .8).
D. (14.7, 1.4)

Question 17 :

• WAEC 2021

Which of the arrangements of radiations below shows decreasing order of wavelengths?

A. X-rays> radio waves > infrared radiations
B. Radio waves> infrared radiations > X-rays
C. Infrared radiations > radio waves > X-rays
D. X-rays> infrared radiations > radio waves

Question 18 :

• WAEC 2021

An electric pressing iron is connected to the mains using an insulated wire. wire becomes very hot.
The heat generated in the wire can be minimized by replacing the wire with one of?

A. Thinner insulation.
B. Greater diameter.
C. Smaller diameter.
D. Thicker insulation.

Question 19 :

• WAEC 2021

In the diagram above, a bulb is lit by drawing 2.0A from 440V a.c. source. Calculate the cost of keeping the bulb on for two days at $0.40 per kilowatt-hour .

A. $16.90
B. $84.48
C. $1690.00
D. $8.48

Question 20 :

• WAEC 2021

Which of the following actions will increase capacitance of a parallel plate capacitor?
I. Decreasing the distance between the plates
II. Increasing the distance between the plates.
III. Increasing the area of the plates overlap.
IV. Avoiding the use of dielectric between the plate

A. I and III only
B. II and III only
C. I and IV
D. . III and IV only