← Back to papers
CSEE 🇹🇿 NECTA ✓ Official NECTA answers

Physics · Paper 2A · 2022

3 questions

📖 View PDF ⬇
🎯 Quiz from this
💰 Sit full exam 200 TZS

3-hour timed simulation · auto-graded · counts toward ranking

Pay & start exam →
Questions (3)

Section A

1. 25 marks

The aim of this experiment is to determine the density of a metre rule. Proceed as follows: (a) Locate the centre of gravity C of the metre rule AB by balancing freely at the knife edge. (b) Suspend 100 g mass on the ruler with distance d = 10 cm from C, adjust the position of the knife edge to get a balance, as shown in the following figure: y -X- A B C 100 gm (c) Record the distance y from the centre of gravity to a knife edge and distance x from knife edge to the known mass of 100 g. (d) Repeat the procedures in 1 (b) and (c) by increasing the distance of 100 g to d = 15 cm, 20 cm, 25 cm and 30 cm.

Diagram for question 1
(i) Tabulate your results in a suitable table showing the values of d, x and y. 5 mk
(ii) Plot a graph of y (cm) against x (cm). 5 mk
(iii) Determine the slope of the graph. 5 mk
(iv) Describe how the slope obtained from the graph is related to the mass of the metre rule provided and hence determine the mass of a ruler. 5 mk
(v) Measure and record the length, width and the thickness of the metre rule provided. 2 mk
(vi) Determine the density of a metre rule. 3 mk

Upgrade to see model answers.

Section B

2. 25 marks

The experiment shown in Figure 2 aims to determine the internal resistance and e.m.f of a given dry cell.

(a) Connect the given electrical components in series, switch must be open. Draw and label clearly your circuit. 10 mk
(b) Set resistance $R = 1 \Omega$, then connect the ammeter and voltmeter as shown in Figure 2. Close the switch and read and record the ammeter reading. Open the switch immediately after taking the readings. 1 mk
(b) Close the switch and record the ammeter reading (I). Adjust the resistance box to get different values of current (I) from 0.1 A to 1.0 A. For each value of current, record the corresponding resistance (R) from the resistance box. 5 mk
(c) Repeat the procedures in 2 (b), setting the value of R to 2 $\Omega$, 3 $\Omega$, 4 $\Omega$ and 5 $\Omega$. 1 mk
(c) Tabulate your results in a suitable table. 5 mk
(d) Tabulate your results including the values of $I$ (ammeter reading) and $V$ (voltmeter reading). 1 mk
(e) Plot a graph of $V$ against $I$. 1 mk
(i) Tabulate your results including the values of R and I. 0 mk
(d) Plot a graph of R (Ω) against I (A). 5 mk
(ii) Plot a graph of R against I. 0 mk
(f) From the graph, determine the slope and the vertical intercept. 1 mk
(e) Determine the slope of the graph and hence determine the e.m.f of the dry cell. 5 mk
(iii) From the graph, determine the slope and the vertical intercept. 0 mk
(g) Use the results obtained in 2 (f) to determine the internal resistance and e.m.f of a given dry cell. 1 mk
(h) What is the aim of doing this experiment? 1 mk
(iv) Use the results obtained in 2 (iii) to determine the internal resistance and e.m.f of a given dry cell. 0 mk
(v) What is the aim of doing this experiment? 0 mk

Upgrade to see model answers.

💡 Unlock all answers & explanations
Premium · 3000 TZS/mo