# WAEC Physics Questions and Answers 2021/2022 Expo Solution

The combination of our free WAEC Physics questions 2021 and the WAEC Physics answers 2021 samples for 2021 theory (essay) & OBJ (objectives) below, will help WAEC candidates to score A or B in this exam.

All the WAEC 2021 Physics Questions and Answers samples below have been completely solved. So each question, including the OBJ questions and the theory questions on this page has been solved each answer is written beside the question.

With the idea you will obtain from this, 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.

You can also try solving the questions by yourself (following the same steps we used) and later compare the answer you get with the ones we have provided on this page. Study the entire WAEC physics questions 2021 samples on this page and check their correct answer.

Page Contents

**WAEC 2021 Physics OBJ Questions and Answers Expo Samples for the objective.**

Use the following WAEC 2021 Physics OBJ Questions and Answers samples for the objective for reference. 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?**

- 10
^{3}ergs - 10
^{6}ergs - 10
^{7}ergs - 10
^{5}ergs

** Correct Answer is C) 10 ^{7} ergs**

**2. Which of these principles does Optical fiber works on?**

- Scattering
- interference
- total internal reflection
- refraction

**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.**

**–**0.8ms^{-1}- 200ms
^{-1} - 0.8ms
^{-1} - -200ms
^{-1} - 0.8kgms
^{-2}

**The correct answer is A. -0.8ms ^{-1}**

**5. Which of this is the correct formula for Kinetic energy?**

- ½ ms
^{2} - ½ kg
^{2} - ½ kx
^{2} - ½ mu
^{2} - ½ mm
^{2}

**The correct answer is D. ½ mu ^{2}**

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})

- 3534joules
- 5000joules
- 2500 joules
- 6250joules
- 622joules

**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}

- 15m
- 45m
- 60
- 90m
- 75m

**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?

- 2.0s
- 3.00s
- 1.5s
- 1.0s
- 0.5s

**The correct answer is D. 1.0s**

### 2021 WAEC past questions 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 P ^{x}V^{y}T^{z} = 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.**

- 233.33N
- 332.33N
- 322.33N
- 323.33N
- 333.33N

**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?**

**Solving:**

Mass of gas per second = ^{200}/_{1000}kgs^{-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

=80N

## Essay and theory sample questions 2021 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

=5×0.03

=1.5N-sec.

**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.}

**Solution.**

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 8^{0} 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 10^{11}m, and the diameter of the sun as 1.4 X 10^{9}

**Solutions**

Let the width of the image = h (m)

tan8^{0} = h/0.5m

h = 0.5 X tan8^{0} = 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 10^{11} =tan0

l = 0.5 X 0.7 X 109/1.5 X 1011 = 0.233X10-2m

=0.23cm

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. So kindly follow the way each of the questions is solved and master them.

I need question and answers 2020

Hi Okika Franklin!! Thanks for showing interest.. Note that WAEC Exam is yet to start..