O Level Physics 5054 Paper 41, May/June 2023

He puts $25{\text{ cm}}^3$ of water in a beaker. The thermometer in Fig. 1.1 shows the temperature ${\theta }_1$ of the water. Record ${\theta }_1$. $${\theta }_1={\text{.................................................... }}^{\circ }\text{C}$$

The teacher has placed some $50\text{ g}$ masses in boiling water. Each mass has been tied to a length of string. The student takes the beaker of water to where the masses are in boiling water. He uses the string to remove one mass from the boiling water and places it carefully into the beaker as shown in Fig. 1.2. He then returns to his workstation and replaces the thermometer in the beaker. The thermometer in Fig. 1.3 shows the maximum temperature ${\theta }_2$ of the water. Calculate the temperature change ${\theta }_2-{\theta }_1$. $${\theta }_2-{\theta }_1=\text{.........................................................}$$

Describe how to ensure that ${\theta }_2$ is measured as accurately as possible.

The beaker is made from a special type of glass. Suggest why it is suitable for this experiment.

Calculate the specific heat capacity $c_m$ of the $50\text{ g}$ mass using the equation: $$c_m=\frac{4.2({\theta }_2-{\theta }_1)}{2(100-{\theta }_2)}$$ $$c_m=\text{........................................... J}\mathrm{/}(\text{g}{}^{\circ }\text{C})$$

Describe two sources of error in the method used to determine $c_m$. 1 ........................................................................................................................................ ........................................................................................................................................... 2 ........................................................................................................................................ ...........................................................................................................................................

Suggest two improvements to the method. 1 ........................................................................................................................................ ........................................................................................................................................... 2 ........................................................................................................................................ ...........................................................................................................................................

Draw a circuit diagram of the circuit.

The student measures the temperature of the room and records it. The recorded result is shown in Fig. 2.2. Fig. 2.3 shows the reading $V_{\text{W}}$ on the voltmeter when the switch is closed. Record the reading $V_{\text{W}}$. $$V_{\text{W}}=\text{...................................................... V}$$

There is a beaker containing ice and water near the thermistor. The student measures the temperature $T_{\text{C}}$ of the ice and water and records it. The recorded result is shown in Fig. 2.4. The thermistor is placed in the beaker of ice and water and after a minute, the voltmeter is read again. Fig. 2.5 shows the reading on the voltmeter when the thermistor is in the beaker of ice and water. Record the reading $V_{\text{C}}$. $$V_{\text{C}}=\text{...................................................... V}$$

Calculate the average change in voltage for one degree temperature change $\mathrm{\Delta }{V}_{\text{AV}}$ using the equation: $$\mathrm{\Delta }{V}_{\text{AV}}=\frac{(V_{\text{C}}-V_{\text{W}})}{(T_{\text{W}}-T_{\text{C}})}$$ State the unit of your answer $$\mathrm{\Delta }{V}_{\text{AV}}=\text{.................... unit ....................}$$

Use your answer to (d)(i) to predict the voltage $V_{\text{PB}}$ across the thermistor when the thermistor is at body temperature. Body temperature is $37{}^{\circ }\text{C}$. You may assume that the average change in voltage for one degree temperature change $\mathrm{\Delta }{V}_{\text{AV}}$ is constant. $$V_{\text{PB}}=\text{...................................................... V}$$

The student is told that if the thermistor is held between a thumb and forefinger for two minutes, the reading on the voltmeter $V_{\text{AB}}$ will be the same as the predicted voltage $V_{\text{PB}}$ in (d)(ii). Two quantities are considered to be equal, within the limits of experimental accuracy, if their values are within 10% of each other. The thermistor is held between the student’s thumb and forefinger for two minutes and the student reads and records the voltage $V_{\text{AB}}$. The recorded result is shown in Fig. 2.6. State whether the student’s results indicate that $V_{\text{PB}}$ and $V_{\text{AB}}$ are equal within the limits of experimental accuracy. Support your statement with a calculation. calculation statement .......................................................................................................................... .....................................................................................................................................

The bottom of mass hanger A is at a height $h$ above the floor as shown in Fig. 3.1. The student places one end of a metre rule on the floor and the other end near to the mass hanger. The top of the metre rule is shown in Fig. 3.2. Record $h$. $$h=\text{................................................... cm}$$

Describe one source of error when measuring $h$ and suggest one improvement to the procedure to reduce this error. source of error ................................................................................................................... ........................................................................................................................................... improvement ..................................................................................................................... ...........................................................................................................................................

The student places a mass $m=5.0\text{ g}$ on mass hanger A. The additional mass causes the mass hanger to descend slowly. The student uses a stop-watch to take three readings of the time taken for mass hanger A to fall to the floor. Using the stop-watch readings in Fig. 3.3, determine an accurate average time $t_{\text{av}}$ for the mass hanger to descend the height $h$. Show your working. $$t_{\text{av}}=\text{...................................................... s}$$

The student repeats the time measurements with different masses placed on hanger A. Record the measurements from (b)(i), in Table 3.1. Complete the headings and give units. Table 3.1

On the grid provided on page 11, plot a graph of average time $t_{\text{av}}$ on the y-axis against the mass $m$ on the x-axis. Draw the best-fit curve.

Describe the relationship between $t_{\text{av}}$ and $m$ shown by the graph.