WAEC physics practical takes 25% of the total mark obtainable in WASSCE physics examination or NECO or GCE.

So many students are eagerly asking about WAEC physics practical questions and answers. The truth is that nobody can give you the real questions. However, a sincere person can only guide you on what you need to know and how to answer the questions.

Kindly note that WAEC will send the 2022 Physics specimen to your teachers; and it is their responsibility to take you through likely questions that will come out in WAEC physics practical.

Furthermore, physics teachers of various secondary schools already have the WAEC practical specimen or set up with them i.e. the list of apparatus that will be needed would have been sent to your school. It is from this that teachers will be able to infer the likely practical questions that might come out in the exam.

According to WAEC Timetable, Physics practical has two alternatives (Alternative A and B) and the questions are divided into three categories which are mechanics, light, and electricity.

That said, you also need to know how make a good **table of values** and how to **plot graph** in physics for you have a good mark in the practical. The link to how to plot graph shows the WAEC standardized way of plotting graph during practical.

It is not about the questions and answers but there are key things to note that I will provide you with in this article.

Paper 3 is a practical test for school candidates or an alternative to practical work paper for private candidates (GCE). Each version of the paper will comprise three questions out of which candidates will be required to answer any two in 2¾ hours for 50 marks.

**Key things to know when answering WAEC Physics practical questions**

- You must have a composite table showing all the parameters in the question with clear headings (make sure you state the unit in the table and graph)
- Your values must be at least 2 decimal places (d.p). Beware of inconsistent d.p.
- Systematic error, gross error, and disregard of instruction are always penalized
- The axes of your graph must be correctly distinguished
- Use reasonable scale
- You must plot all your points correctly

**Likely precautions in WAEC physics practical**

**Mechanics**

- Avoided parallax error in reading stopwatch/clock/metre rule
- Noted/corrected/avoided zero error on stopwatch/clock/metre rule
- Avoided draught
- Avoided conical oscillation
- Ensured that support was rigid
- Ensured bob of pendulum was free from table

**Light**

- Avoided parallax error in reading metre rule/protractor
- Optical pins inserted vertically
- Reasonable spacing of pins
- Well sharpened pencil used
- Repeated readings shown on table
- Surface of prism cleaned
- Surface of lens cleaned
- Lens kept upright

**Electricity**

- Key opened in between readings
- Tight connections used
- Avoided parallax error when taking readings on voltmeter or ammeter
- Clean terminal ensured
- Avoided zero error on voltmeter or ammeter
- Repeated readings shown on table

**WAEC Physics Practical Sample Questions And Answers**

**Sample Question 1**

You are provided with a metre rule, a knife-edge, set of masses, inextensible string, retort support and other necessary apparatus.

i. Place the metre rule on the knife edge. Read and record the point G where the metre rule balances horizontally, as shown in Fig (a).

ii. Suspend the metre rule at G with the aid of the string provided and attach the string to the retort support as shown in Fig 1(b). Keep the string attached to this point throughout the experiment.

iii. Attach the mass M0 at the 80cm mark of the metre rule. Determine the distance of y from G. Keep M0 at this position throughout the experiment.

iv. Suspend a mass M= 40g on the side AG and adjust its position until the metre rule balances horizontally.

v. Measure and record the distance of x of M from G. Evaluate x−1

vi. Repeat the procedure for four other values of M= 60g, 80g, 100g and 120g. Measure and record x and evaluate x−1 in each case.

vii. Tabulate the readings.

viii. Plot a graph of M on the vertical axis and x on the horizontal axis, starting both axes from the origin (0,0).

ix. Determine the slope s of the graph:

x. Given that s = yM0, determine M0

xi. State two precautions taken to obtain accurate results.

(b) i. Define the moment of a force about a point.

ii. A uniform metre rule is suspended by an inextensible string at its centre of gravity. If a mass of 60g is placed at the 25cm mark, what mass should be placed at the 80cm mark of the metre rule to balance it horizontally?

**Answer**

S/N | M(g) | x(cm) | x−1 |

(cm−1

x−1 |

(x10−3

) | ||||

1 2 3 4 6 | 40.0 60.0 80.0 100.0 120.0 | 37.50 25.0 18.75 15.00 12.50 | 0.027 0.040 0.055 0.067 0.08 | 27.00 40.00 53.00 67.00 80.00 |

Note: G = 50.0cm, y = 30.0cm

viii.

ix. Slope = △*M*△/*X*−1

= *M*2*X*−12−*M*1*X*−11

= 120.0−4080.0−27

= 80/53

= 1.509 x 103

= 1509

x. S = yM0

1509 = 30M0

M0 = 1509/30

M0 = 50.3

xi. **Precautions**:

– Avoided parallax error in reading metre rule

– Noted/corrected/Avoided zero error on metre rule

– Avoided draught

– Ensured that support was rigid/firm

– Repeated readings shown on the table

– Ensured mass does not touch or rest on the table.

(b) i. **Definition of the moment of a force about a point**: It is the product of the force and the perpendicular distance between the line of action of the force and the point.

Sum of clockwise moment = sum of anticlockwise moment

M x 30 = 60 x 25

M = 60×2530

= 50

**Sample Question 2**

You are provided with a potentiometer **AB**, a 10Ω standard resistor **R**, a battery of emf 4.5V, a jockey **J, **and other necessary materials.

- Connect a circuit as shown in the diagram above.
- Close key
**K**. Without**J**making contact with**AB**, read and record the ammeter reading**I**. Open the key. - Use the jockey to make contact with
**AB**at the 20cm mark such that**AJ**= x = 20cm. Close the key, read and record the ammeter reading. - Evaluate x
^{−1} - Repeat the procedure for values of x= 35cm, 45cm, 60cm, and 80cm respectively.
- Tabulate your readings.
- Plot a graph with
**x**^{−1}*i*on the horizontal axis, starting both axes from the origin (0, 0). - Determine the slope, s, of the graph.
- From your graph, determine the value l
*o*of I1 for which x^{−1}= 0. - Evaluate
*I**o/**I*

- State
**two**precautions taken to obtain accurate results.

(b)i. Define the emf of a battery.

ii. A cell X of emf 1.018V is balanced by a length of 50.0cm on a potentiometer wire. Another cell Y is balanced by a length of 75.0cm on the same wire. Calculate the emf of Y.

**Answer**

Electricity

I = 0.36A

xcm |

IA |

X−1cm−1 |

20.0 | 1.14 | 0.050 |

35.0 | 0.90 | 0.029 |

45.0 | 0.84 | 0.022 |

60.0 | 0.78 | 0.017 |

80.0 | 0.66 | 0.013 |

Slope (s) = △*X*^{}−^{1}/△*I*

= 0.08−0.011.68−0.644=0.071.036

From the graph,

When X^{−}^{1} = 0

I0 of I1 = 0.448A

x. Evaluate *I*0/*I*

= 0.448/0.36

= 1.244

**Precaution; **

- The key was opened when readings were not taken.
- I ensured tight connections of the connecting wire
- I avoided parallax errors when reading the potentiometer.

(bi)** Define emf of a battery:** The e.m.f of a cell is the potential difference across its terminals when it is in an open circuit. i.e. not Supplying current to an external circuit.

ii. A cell **x **emf is 1.018V.

Length1

on the potentiometer x = 50.0cm

Length2

on the potentiometer, **y**,= 75.0cm

A cell **Y **emf is?

**Solution**

By formula;

*E*1/*E*2 = *L*2/*L*1

1.018/*E*2=75.0/50.0

75.E2 = 1.018 x 50

E2 = 1.018×5075

E2= 0.612V.