2026 NECO Practical Physics Questions and Answers

2026 NECO Practical Physics Questions and Answers

REAL ANSWERS LOADING….

JOIN OUR WHATSAPP GROUP  https://chat.whatsapp.com/KgIfz9cevVFK6nUwwZn9Cr

Examination Instructions

You are provided with:

• A retort stand with clamp
• A pendulum bob
• A light inextensible thread
• A metre rule
• A stopwatch

Carry out the experiment carefully and record all readings in the spaces provided.

Apparatus Required

• Retort stand
• Clamp
• Pendulum bob
• Thread
• Metre rule
• Stopwatch

Question 1

You are provided with the following specimens:

• Specimen A: Retort stand with clamp
• Specimen B: Pendulum bob
• Specimen C: Light inextensible thread
• Specimen D: Metre rule
• Specimen E: Stopwatch

Instructions

Use the specimens provided to carry out the experiment and answer the questions that follow.

(a) Assemble Specimens A, B, and C to form a simple pendulum.

Measure the length $L$ of the pendulum for five different values between 30 cm and 70 cm.

For each length:

i. Set the pendulum into small oscillations.

ii. Measure the time $t$ for 20 complete oscillations.

iii. Determine the period T=t20T = \frac{t}{20}T=20t​.

iv. Calculate T2T^2T2.

Record your observations in a suitable table.

(b) Plot a graph of T2T^2T2 against $L$.

(c) Determine the gradient of the graph.

(d) Hence calculate the acceleration due to gravity, $g$.

(e) State two precautions taken during the experiment.

(f) State two possible sources of error.

Instructions to Candidates

1. Assemble Specimens A, B and C to form a simple pendulum.
2. Suspend the pendulum securely on the retort stand.
3. Measure the length of the pendulum from the point of suspension to the centre of the bob.
4. Release the pendulum gently from a small angle (less than 10°).
5. Measure the time for 20 complete oscillations.
6. Repeat the experiment for five different lengths.
7. Record all observations in the table provided.

(a) Complete the Observation Table

(b) Plot a Graph

Plot a graph of:

• Vertical Axis (Y-axis): T² (s²)
• Horizontal Axis (X-axis): Length L (m)

A straight-line graph should be obtained.

(c) Determine the Gradient of the Graph

Using two well-spaced points:

Point A = (0.30, 1.21)

Point B = (0.70, 2.82)

Gradient=2.82−1.210.70−0.30\text{Gradient}=\frac{2.82-1.21}{0.70-0.30}Gradient=0.70−0.302.82−1.21​ =1.610.40=\frac{1.61}{0.40}=0.401.61​ $$=4.03$$

Gradient = 4.03 s²/m

2026 NECO Practical Physics Questions and Answers

(d) Hence Determine the Value of g

Since

T2=4π2gLT^2=\frac{4\pi^2}{g}LT2=g4π2​L

The slope of the graph is

4π2g\frac{4\pi^2}{g}g4π2​

Therefore

g=4π2Slopeg=\frac{4\pi^2}{\text{Slope}}g=Slope4π2​ 4π2=39.484\pi^2=39.484π2=39.48

Hence

g=39.484.03g=\frac{39.48}{4.03}g=4.0339.48​ g=9.80 m/s2g=9.80\,\text{m/s}^2g=9.80m/s2

Answer:

g≈9.8 m/s2g\approx9.8\,\text{m/s}^2g≈9.8m/s2

(e) State Four Precautions

Answer

1. Ensure the pendulum swings through a small angle (less than 10°).
2. Release the bob gently without applying extra force.
3. Measure the length from the point of suspension to the centre of the bob.
4. Record the time for many oscillations (e.g., 20) to reduce timing errors.

(f) State Four Sources of Error

Answer

1. Human reaction time when starting and stopping the stopwatch.
2. Air resistance acting on the pendulum bob.
3. Friction at the point of suspension.
4. Parallax error while reading the metre rule.

Expanded Worked Solution

Step 1: Measuring the Length

The length of the pendulum is not simply the length of the thread. It is measured from the point where the thread is attached to the support down to the centre of the pendulum bob. Measuring to the top or bottom of the bob would introduce systematic error.

Step 2: Timing the Oscillations

Instead of timing a single swing, the time for 20 complete oscillations is measured. This reduces the effect of human reaction time because any start/stop error is spread over many oscillations.

For example, if the time for 20 oscillations is 22.0 s:

T=22.020=1.10 sT=\frac{22.0}{20}=1.10\,\text{s}T=2022.0​=1.10s

The period $T$ is the time taken for one complete oscillation.

Step 3: Calculating T2T^2T2

The theoretical relationship for a simple pendulum involves the square of the period. Therefore, each measured period is squared.

For the first reading:

$$T=1.10\text{s}$$ T2=(1.10)2=1.21 s2T^2=(1.10)^2=1.21\,\text{s}^2T2=(1.10)2=1.21s2

This process is repeated for each length.

Step 4: Plotting the Graph

The graph of T2T^2T2 against $L$ should produce a straight line because the theory predicts a direct proportional relationship:

T2∝LT^2 \propto LT2∝L

A straight line confirms that the experimental results are consistent with the theory of simple harmonic motion.

Step 5: Determining the Gradient

The gradient is calculated from two well-separated points on the best-fit line:

Gradient=ΔT2ΔL\text{Gradient}=\frac{\Delta T^2}{\Delta L}Gradient=ΔLΔT2​

Substituting the values:

2.82−1.210.70−0.30=1.610.40=4.03\frac{2.82-1.21}{0.70-0.30} =\frac{1.61}{0.40} =4.030.70−0.302.82−1.21​=0.401.61​=4.03

Step 6: Calculating the Acceleration Due to Gravity

The relationship

T2=4π2gLT^2=\frac{4\pi^2}{g}LT2=g4π2​L

shows that the gradient equals 4π2g\frac{4\pi^2}{g}g4π2​. Rearranging gives:

g=4π2Gradientg=\frac{4\pi^2}{\text{Gradient}}g=Gradient4π2​

Using the calculated gradient:

g=39.484.03=9.80 m/s2g=\frac{39.48}{4.03}=9.80\,\text{m/s}^2g=4.0339.48​=9.80m/s2

This value is very close to the accepted acceleration due to gravity at the Earth’s surface, indicating that the experiment was carried out accurately.

2026 NECO Practical Physics Questions and Answers

Discussion of Results

The results show that:

• As the length of the pendulum increases, the period of oscillation also increases.
• The graph is approximately a straight line, confirming the theoretical relationship between T2T^2T2 and $L$.
• The calculated value of $g$ agrees with the accepted value of approximately 9.81 m/s², demonstrating the reliability of the experiment within normal experimental error.

Educational Importance of the Experiment

This practical helps students:

• Understand simple harmonic motion.
• Learn how to measure time and length accurately.
• Develop graph-plotting and gradient calculation skills.
• Appreciate how experimental data can be used to determine physical constants such as the acceleration due to gravity.

Possible Viva Voce Questions and Answers

1. Why is the pendulum released gently?
To avoid giving it extra velocity, which could affect the motion and the measured period.

2. Why is the oscillation angle kept small?
Small angles ensure the motion closely approximates simple harmonic motion, making the formula valid.

3. Why are 20 oscillations timed instead of one?
Timing multiple oscillations reduces the percentage error due to human reaction time.

4. Why is the length measured to the centre of the bob?
The centre of mass of the bob is the correct reference point for the pendulum length.

5. What physical quantity is being determined in this experiment?
The acceleration due to gravity, $g$.

Examiner’s Marking Guide (20 Marks)