O Level Physics 5054 Paper 42, May/June 2026

Measure the length $l$ of the pendulum in Figure 1.1. Record your measurement in centimetres to the nearest $0.1\text{ cm}$. $l=\text{.................................................... cm}$

Figure 1.1 has been drawn to a scale of one-fifth full size. Calculate the actual length $L$ of the pendulum in metres. Record your answer in the first column of Table 1.1.

procedure The student: • gives the bob a small sideways displacement and releases it so that it oscillates • measures the time $t$ for 20 oscillations of the pendulum. The stopwatch reading is shown in Figure 1.2. Record $t$ to 3 significant figures in the second column of Table 1.1.

Calculate the period $T$ of the pendulum. The period is the time for 1 oscillation of the pendulum. Record, in Table 1.1, your answer to 3 significant figures.

The student: • adjusts the length of the string until the length $L$ of the pendulum is $0.700\text{ m}$ • repeats the procedure in 1(b). The student records the results in Table 1.1. Using data from Table 1.1, show that $T$ is not proportional to $L$.

The acceleration due to gravity in ${\text{m/s}}^2$ can be calculated using the equation shown. $$g=\frac{39L}{T^2}$$ Calculate a first value $g_1$ for the acceleration due to gravity, using your value of $L$ from 1(a)(ii) and your value of $T$ from 1(b)(ii). Show your working and give your answer to 2 significant figures. $g_1={\text{................................................ m/s}}^2$

Calculate a second value $g_2$ for the acceleration due to gravity, using the data for $L=0.700\text{ m}$ from Table 1.1. $g_2={\text{................................................ m/s}}^2$

Two quantities can be considered to be the same within the limits of experimental accuracy if their values are within 10% of each other. Compare your value of $g_1$ from 1(d)(i) with your value of $g_2$ from 1(d)(ii). State if your two values can be considered to be the same. Support your statement with a calculation. calculation statement ..................................................................................................................................

State one technique that the student uses when doing the experiment to ensure that the results are accurate.

procedure The student: • pours $200{\text{ cm}}^3$ of hot water into beaker P • places a thermometer into the water • waits until the thermometer reading has stopped increasing • records the temperature $\theta$ of the hot water • immediately starts a stopwatch • allows the hot water to cool for $240\text{ s}$ • measures the temperature $\theta$ of the water in the beaker, and records it in Table 2.1 at time $t=240\text{ s}$. The maximum thermometer reading is shown in Figure 2.2. Read the temperature $\theta$ of the hot water in beaker P at time $t=0$. Record your reading in the second column of Table 2.1.

The student repeats the procedure for beaker Q. The thermometer readings are shown in Table 2.1. Add units to the column headings in Table 2.1.

Use the temperature readings in Table 2.1 to calculate the temperature decrease of the hot water in beaker P and in beaker Q after cooling for $240\text{ s}$. temperature decrease in beaker P = .......................................................... °C temperature decrease in beaker Q = .......................................................... °C

Calculate the rate of temperature decrease of the water in each beaker using the equation shown. $$\text{rate of temperature decrease}=\frac{\text{temperature decrease}}{\text{time}}$$ Give your answers to 2 significant figures. rate of temperature decrease from the water in beaker P = ................................................... °C/min rate of temperature decrease from the water in beaker Q = ................................................... °C/min

State which beaker P or Q has the more effective method of reducing the rate of temperature decrease. Explain how you reached your conclusion.

State two factors that must be controlled to make a valid comparison between the rates of temperature decrease of beaker P and beaker Q. 1 ................................................................................................................................................ 2 ................................................................................................................................................

This experiment compares the effect of a layer of insulation with the effect of a lid on the rate of decrease of temperature. A student wants to find how the rate of decrease of temperature of the water in a beaker surrounded by a layer of insulation compares with the rate of decrease of temperature of the water in a beaker with no insulation. Suggest one change to the apparatus that will enable this new comparison to be made.

Handling a beaker containing hot water is dangerous. State one safety precaution that the student takes when doing the experiment.

procedure The student: • connects a $12\mathrm{\Omega }$ resistor into the gap between terminals P and Q in the circuit • connects a voltmeter to measure the potential difference across the resistor • closes the switch • measures and records the potential difference $V$ across the resistor and the current $I$ in the circuit • opens the switch • removes the $12\mathrm{\Omega }$ resistor. On Figure 3.1, using the correct circuit symbol, draw a resistor connected between terminals P and Q.

On Figure 3.1, using the correct circuit symbol, draw a voltmeter connected to measure the potential difference across the resistor.

The voltmeter and ammeter readings are shown in Figure 3.2. Record, in Table 3.1, the potential difference $V$ across the $12\mathrm{\Omega }$ resistor.

Record, in Table 3.1, the current $I$ in the circuit with the $12\mathrm{\Omega }$ resistor.

The student repeats the procedure for resistors of value $15\mathrm{\Omega }$, $18\mathrm{\Omega }$, $22\mathrm{\Omega }$ and $33\mathrm{\Omega }$. The student’s results are shown in Table 3.1. Table 3.1 On the grid provided in Figure 3.3, plot a graph of $V$ on the $y$-axis against $I$ on the $x$-axis. Start the $x$-axis from $I=0\text{ A}$. Do not start the $y$-axis from $V=0\text{ V}$. Draw the straight line of best fit.

Determine the gradient $G$ of your line. Show all working, and indicate on the graph the values you use. $G=\text{.........................................................}$

The magnitude of gradient $G$ of your line is equal to the resistance $r$ of the battery. Write down the value of $r$. Record your answer to the nearest ohm. $r=\text{...................................................... }\mathrm{\Omega }$

The student is able to use the graph to find the predicted e.m.f of the battery. Describe how the student uses the voltmeter to measure the actual e.m.f. of the battery.

When doing the experiment, it is important that the terminals P and Q are not allowed to come into contact with each other at any time. Suggest why terminals P and Q must not touch.