0625 Physics November 2025 Question Paper 62

1 A student investigates the reflection of light by a plane mirror.

The student’s ray-trace is shown full-size in Fig. 1.1. L N M 1 P R 2 Fig. 1.1

(a) The student: • draws line LN • labels the mid-point of LN with the letter M • draws a line PR parallel to LN and 10.0 cm below it

On Fig. 1.1, draw a normal to LN at the point M. Extend the normal downwards until it crosses the line PR. Label the point at which the normal crosses PR with the letter Q. [1] , ,

(b) On Fig. 1.1, draw a line 14.0 cm long from point M at an angle θ = 10°, as shown in Fig. 1.2.

Label the other end of the line O. [2] L N O M θ Fig. 1.2

(c) The student: • places the reflecting surface of a mirror along the line LN, with its reflecting surface facing the bottom of the page, and with the centre of the mirror at M • positions a light source and slit so that a ray of light passes along the line OM towards M • marks two small crosses X1 and X2, a suitable distance apart on the ray reflected from the mirror • removes the mirror and the illuminated slit.

(i) On Fig. 1.1, draw a line joining M to X1 and X2.

Continue the line until it crosses the line PR and label the point where it crosses PR with the letter T. [1]

(ii) Measure the length a of the line QT in centimetres to the nearest millimetre and the length b of the line MT in centimetres to the nearest millimetre. Record your measurements below and in Table 1.1.

a = cm

b = cm

[1] , ,

(d) Calculate the ratio r = a b . Record your answer in Table 1.1.

Give your answer to 2 significant figures.

Table 1.1 θ / ° a / cm b / cm r = a b 10 20 4.2 12.8 0.33 30 6.8 13.7 0.50

[2]

(e) The student repeats the procedure in (b) and (c) for values of θ = 20° and θ = 30°.

The student’s results are recorded in Table 1.1.

The student states that r is directly proportional to θ.

State if you agree with the student.

Use values from Table 1.1 to justify your answer. statement justification [2]

(f) Suggest what the student can do to have more confidence in their answer to part (e) [1]

(g) Suggest one source of inaccuracy in this experiment, even if it is carried out very carefully [1]

[Total: 11] , ,

2 A student investigates an electric circuit to find the resistance of an unknown resistor Z.

The student sets up the incomplete circuit shown in Fig. 2.1. There is a gap between the points labelled X and Y. V X Z Y + – Fig. 2.1

(a) The student: • closes the switch • records the voltmeter reading V0 • opens the switch.

The reading on the voltmeter is shown in Fig. 2.2.

Record the voltmeter reading V0.

V 3 4 5 2 1 0 Fig. 2.2

V0 = V [1] , ,

(b) The student: • connects a 10 Ω resistor between points X and Y • closes the switch • records, in Table 2.1, the reading V on the voltmeter • opens the switch • repeats this procedure for resistors of resistances R = 22 Ω, 39 Ω, 47 Ω and 68 Ω. Table 2.1 resistance R / Ω voltmeter reading V / V current I / A 10 1.35 22 2.20

0.10 39 2.85

0.073 47

0.064 68 3.37

0.050

(i) Use the voltmeter reading in Table 2.1 when the 10 Ω resistor is connected between X and Y to calculate the current I in the circuit. Use the equation: I = V R

Record your value of I in Table 2.1 to 2 significant figures. [2]

(ii) The voltmeter reading V for the 47 Ω resistor is missing. Calculate V.

V = V

Add your answer to Table 2.1. [1] , ,

(c) Plot a graph of V / V (y-axis) against I / A (x-axis). Start your axes at the origin (0,0).

Draw a best-fit straight line.

[4]

(d) Determine the gradient G of your line. Show all working and indicate on the graph the values you use.

G = [2]

(e) The gradient of your line is numerically equal to the resistance RZ of the unknown resistor Z.

Write down the value of the resistance RZ.

Record your answer to the nearest ohm.

RZ = Ω [1]

[Total: 11] , ,

3 A student investigates the cooling of water.

The student sets up the apparatus shown in Fig. 3.1. beaker thermometer stand Fig. 3.1

(a) The student records the room temperature θR. θR = 21.5 °C The student: • pours 60 cm3 of hot water into the beaker • waits for 30 s • measures, and records in Table 3.1 at time t = 0, the temperature θ of the water • immediately starts a stop-watch and measures the temperature of the water at one-minute intervals for 5 minutes.

The reading on the thermometer for time t = 0 is shown in Fig. 3.2. °C 90 80 Fig. 3.2 , ,

(i) Record the temperature in Table 3.1 to the nearest 0.5 °C. [1]

(ii) Complete the time t column. [1] Table 3.1 time t / temperature θ / °C 0 80.5 75.5 71.0 67.5 64.0

(b) (i) Suggest why the student waits for 30 s before measuring the initial temperature of the hot water [1]

(ii) State how the student ensures that the temperature readings are as accurate as possible [1]

(c) (i) Calculate the decrease in temperature Δθ  of the hot water during the first two minutes of cooling.   Δθ  = °C [1]

(ii) Calculate the average rate of cooling R1 of the hot water during the first two minutes of cooling.

Use the equation: R1 = decrease in temperature time

Include the unit in your answer.

R1 = unit = [2]

(iii) Calculate the average rate of cooling R2 of the hot water during the final two minutes of cooling.

R2 = [1] , ,

(d) Use your answers in (c)(ii) and (c)(iii) to write a conclusion about the way in which hot water in a beaker cools [1]

(e) The water in the beaker is left to continue cooling.

(i) Estimate the temperature of the water θ5 after a further 5 minutes of cooling.

θ5 = °C [1]

(ii) Estimate the temperature of the water θ50 after a further 50 minutes of cooling.

θ50 = °C [1]

[Total: 11] , ,