EXPO: WAEC Physics Questions and Answers 2021/2022 – Theory Objectives (OBJ).
WAEC Physics Questions and Answers: This WAEC 2021 Physics expo question and answer is free for all candidates writing this year exams. If you are among those writing 2021 WAEC Examination, Feel free to expect free answer here.
The West African Examinations Council is an examination that is for all the west African country (Ghana, Nigeria, Sierra Leone, Liberia, and Gambia).
See Also: WAEC Physics Syllabus
WAEC Physics Expo Runs for Theory and OBJ For Wednesday 15th September 2021.
This is 2021 free WAEC Physics Expo answers 2021 samples for 2021 theory (essay) paper 2 & OBJ (objectives) paper 1 for 2021 WAEC candidates.
With this idea, you will obtain from this material ideas on questions pattern, you will be able to even solve every other question (including the WAEC past questions and answers on physics) by yourself.
The theory section will give you the “showing working” of each of the WAEC Physics essay and theory sample questions and answers for 2021 (i.e paper 2). Study the steps and master them in case you see similar questions during the exam.
WAEC 2021 Physics OBJ Questions and Answers Samples.
Use the following WAEC 2021 Physics Objective Questions and Answers samples for the OBJ paper 1 for reference.
Kindly Study the entire sample WAEC physics questions 2021 below, and check their correct answer. Proceed to the theory section at the bottom to see how each question is solved.
1. One Joule is Equal to?
- 103 ergs
- 106 ergs
- 107 ergs
- 105 ergs
Correct Answer is C) 107 ergs
2. Which of these principles does Optical fiber works on?
- total internal reflection
The correct answer is C) total internal reflection
3. Why is the base of an electric iron usually brightly polished?
- To Make it smooth and frictionless
- Make it rust-proof
- Reduce heat loss by radiation
- Make it more durable
Correct Answer is: C) to reduce heat loss by radiation
5. A riffle of mass 15kg fires a bullet of mass 60g with a velocity of 200ms-1. Calculate the recoil velocity of the riffle.
The correct answer is A. -0.8ms-1
5. Which of this is the correct formula for Kinetic energy?
- ½ ms2
- ½ kg2
- ½ kx2
- ½ mu2
- ½ mm2
The correct answer is D. ½ mu2
6. If the efficiency of a machine is 60%, find in joules, the work done by the student using this machine to raise a load of 150kg through a vertical distance of 2.5m (g = 10ms-1)
- 2500 joules
The correct answer is D. 6250 Joules
7. Calculate the height from which a body is released from rest if its velocity just before hitting the ground is 30ms-1
The correct answer is B. 45m
8. A mango fruit from the top of its tree which is 5m long drops to the ground. How long does it take the mango to reach the ground?
The correct answer is D. 1.0s
2021 WAEC Past Questions and Answers for Physics.
Additionally, the following WAEC past questions and answers on physics objective will help you to get more ideas on how to solve physics WAEC questions.
Also, do well to scroll to the bottom to see how each of these questions is solved to arrive at the answer.
1. The equation PxVyTz = constant is Gay-Lussac’s law if____?
- x = 0, y = 0 and z = 1
- x = 1, y = 0 and z = -1
- x = 1, y = 1 and z = 1
- x = 0, y= 0 and z = 0
- x = -1, y = 1 and z = 0
The correct answer is B. x = 1, y = 0 and z = -1
2. Calculate the effort put into a machine whose efficiency is 75% and lifts a load of 1000N, if its velocity ratio is 4.
The correct answer is E. 333.33N
Theory question: A rocket is burning fuel at the rate of 200gs-1 and ejecting all the gas in one direction at the rate of 400ms-1. What is the maximum weight the rocket can have if it is going to move vertically upwards?
Mass of gas per second = 200/1000kgs-1.
Velocity of expulsion = 400ms-1.
Momentum change per second = 200/1000 x 400kgms-2.
From Newton’s second law, we have F =W =200/1000 x 400N
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Physics Essay and theory sample Questions and Answers for paper 2.
Below are the showing working of the WAEC Physics essay and theory sample questions and answers for 2021 paper 2.
Study the steps and master them in case you see similar questions during the exam.
1. A stationary ball is hit by an average force of 50N for a time range of 0.03sec. Calculate the impulse experienced by the ball.
Solution: impulse (I) = Ft
2. Calculate the recoil velocity of a riffle of mass 15kg which fires a bullet of mass 60g with a velocity of 200ms-1.
Mass of the riffle = 15kg, while the mass of the bullet = 60g
The velocity of the bullet = 200ms-1.
The momentum before firing is zero
Momentum after firing = 15 x V + 60/100 X 200 = 15v + 12
Since the momentum is conserved, we will have;
15v + 12 =0
v = –12/15 = -0.8ms-1
Question 3. i. What is the width of the image of an object which subtends an angle of 80 at the pinhole of a camera 0.5m long?
ii. How long is the image of the sun on this camera? Take the mean distance of the sun as 1.5 X 1011m, and the diameter of the sun as 1.4 X 109
Let the width of the image = h (m)
tan80 = h/0.5m
h = 0.5 X tan80 = 0.5 X 0.1405m = 7cm Ans.
Let the radius of the sun be l (m)
l/0.5 = 0.7 X 109/1.5 X 1011 =tan0
l = 0.5 X 0.7 X 109/1.5 X 1011 = 0.233X10-2m
Therefore, the diameter of the image = 0.46cm
The combination of the above WAEC Physics questions 2021 and the WAEC Physics answers 2021 samples for essay, theory, and OBJ (objectives) above, will surely help candidates a lot.
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