Paper 6 style practice paper: Alternative to practical — question paper

Section A: Practical measurements[20 marks]

Answer all questions in the spaces provided. The marks in Section A total 20.

1. 1

   A student determines the density of a small metal cylinder. The mass, found on a balance, is 178.0 g. The cylinder’s diameter is measured with a rule at three positions: 2.50 cm, 2.52 cm and 2.48 cm. Its length is measured as 5.00 cm.

   1. (a)

      Calculate the average diameter and explain why several readings were taken.

      [2]
   2. (b)

      Show that the volume of the cylinder is about 24.5 cm³. (Volume of a cylinder = πd²L/4.)

      [3]
   3. (c)

      Calculate the density of the metal in g/cm³.

      [1]
2. 2

   A student measures the resistance of a lamp using the circuit shown: a battery, an ammeter in series with the lamp, a voltmeter across the lamp, and a variable resistor to change the current. The lamp glows dimly at first and brightly at higher currents.

   1. (a)

      State where the ammeter and voltmeter are connected, and why.

      [2]
   2. (b)

      The voltmeter reads 2.0 V and the ammeter reads 0.40 A. Calculate the resistance at this setting.

      [2]
   3. (c)

      The experiment is repeated at higher currents. State and explain how the lamp’s resistance changes, and describe the evidence that shows it.

      [3]
3. 3

   A student investigates a cooling curve. A heated solid block is allowed to cool and its temperature is recorded every 30 s. The block melts at 48 °C. Part of the results table is shown.

   Cooling results

   Time / s	0	30	60	90	120	150	180
   Temperature / °C	61	55	48	48	48	44	40

   1. (a)

      State the time interval during which the block was melting, and explain how the table shows it.

      [2]
   2. (b)

      Describe how the rate of cooling before the plateau compares with the rate after it.

      [2]
   3. (c)

      Suggest one improvement to the experiment so that the plateau is shown more clearly.

      [3]

Section B: Planning, observations and analysis[20 marks]

Answer all questions in the spaces provided. The marks in Section B total 20.

1. 4

   A student investigates how the extension of a spring depends on the load. Available equipment: a clamp stand, a spring, a mm rule, and a set of 1.0 N weights.

   Spring results

   Load / N	1.0	2.0	3.0	4.0
   Extension / mm	5.0	10.0	15.0	20.0

   1. (a)

      Describe how to measure the extension for one load, so that the measurement is as reliable as possible.

      [3]
   2. (b)

      Plot a graph of extension (y-axis) against load (x-axis) using the results table, and state what the shape of the graph shows.

      [3]
   3. (c)

      Use the graph to predict the extension for a load of 3.5 N.

      [1]
2. 5

   A class measures the speed of sound in air using two microphones connected to an electronic timer. Clapping near microphone A starts the timer; the sound reaching microphone B stops it. The microphones are 102 m apart, and the timer reads 0.30 s.

   1. (a)

      Calculate the speed of sound from these results.

      [2]
   2. (b)

      The measurement is repeated three times, giving 0.30 s, 0.28 s and 0.32 s. Explain why repeating and averaging improves the result.

      [2]
   3. (c)

      State one other practical improvement for this experiment.

      [2]
3. 6

   A radioactive source with a half-life of about 1 minute is used in a classroom simulation of decay counting. The teacher suggests using 64 dice: each roll of a die showing a six represents a nucleus that has decayed and is removed.

   1. (a)

      Explain why removing the sixes models radioactive decay.

      [2]
   2. (b)

      Predict the expected number of dice remaining after each of the first two rolls, and name the quantity that halves each time in the real process.

      [2]
   3. (c)

      The class actually rolls 34 sixes first, not 32. Explain whether this disproves the model.

      [2]
   4. (d)

      State one limitation of the dice model compared with real radioactive decay.

      [1]