Leave blank 9 Turn over *N31196A0916* Question 1C You are to plan an investigation of how the magnetic field strength varies along the axis of a solenoid. You are then to analyse a set of data from such an experiment. (a) (i) A solenoid is set up as shown in the diagram below. Add to the diagram the circuit you would connect to the solenoid to set and maintain a known value of current in the solenoid. (3) (ii) Draw how you would place a Hall probe to measure the magnetic field strength at a point along the axis a distance x from the centre C of the solenoid. You should draw the Hall probe outside the solenoid and should take care to show the orientation of the chip (sensor) correctly. (1) (iii) Describe how you would determine the distance x. You may add to the diagram if you wish. ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ ................................................................................................................................ (2) QUESTION 1C CONTINUES ON THE NEXT PAGE x Axis C
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Question 1C
You are to plan an investigation of how the magnetic field strength varies along the axis of a solenoid. You are then to analyse a set of data from such an experiment.
(a) (i) A solenoid is set up as shown in the diagram below. Add to the diagram the circuit you would connect to the solenoid to set and maintain a known value of current in the solenoid.
(3)
(ii) Draw how you would place a Hall probe to measure the magnetic field strength at a point along the axis a distance x from the centre C of the solenoid. You should draw the Hall probe outside the solenoid and should take care to show the orientation of the chip (sensor) correctly.
(1)
(iii) Describe how you would determine the distance x. You may add to the diagram if you wish.
(b) The solenoid has a length of 276 mm and has 337 turns. When the current in the solenoid was adjusted to 500 mA, the calibrated Hall probe indicated that the magnetic field strength at the centre of the solenoid was 0.761 mT.
The magnetic field strength B at the centre of a solenoid having n turns per metre is given by:
B = µ0 n I
when the current in the solenoid is I.
Discuss the extent to which you think that the Hall probe is correctly calibrated.
(c) The following data were obtained when the magnetic field strength B was measured along the axis at different distances x from the centre of the solenoid, keeping the current constant at 500 mA.
x / mm B / mT
0 0.761
40 0.760
80 0.706
120 0.549
140 0.330
150 0.217
160 0.151
180 0.077
200 0.032
Plot a graph of B against x on the grid opposite.
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(d) Theory suggests that the magnetic field strength at the end of a long solenoid is exactly half that at its centre. Discuss the extent to which this experiment supports this suggestion.
You are to plan an investigation of how the magnetic field strength varies along the axis of a coil. You are then to analyse a set of data from such an experiment.
(a) (i) A flat circular coil is set up as shown in the diagram below. Add to the diagram the circuit you would connect to the coil to set and maintain a known value of current in the coil.
(3)
(ii) Draw how you would place a Hall probe to measure the magnetic field strength at a point along the axis a distance x from the centre C of the coil. You should be careful to show the orientation of the Hall chip (sensor) correctly.
(1)
(iii) Describe how you would determine the average diameter of the coil. You may add to the diagram if you wish.
(b) The coil has a diameter of 124 mm and has 70 turns. When the current in the coil was adjusted to 500 mA, the calibrated Hall probe indicated that the magnetic field strength at the centre of the coil was 0.350 mT.
The magnetic field strength B at the centre of a coil having a radius r and N turns is given by
B NIr
=µ0
2
when the current in the coil is I.
Discuss the extent to which you think that the Hall probe is correctly calibrated.
(c) The following data were obtained when the magnetic field strength B was measured along the axis at different distances x from the centre of the coil, keeping the current constant at 500 mA.
x / mm B / mT
0 0.350
20 0.304
40 0.219
50 0.163
60 0.120
80 0.071
100 0.039
120 0.024
Plot a graph of B against x on the grid opposite.
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QUESTION 2C CONTINUES ON THE NEXT PAGE
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(d) Theory suggests that when x = r, the radius of the coil, the magnetic fieldstrength is 1 8/ of the field strength at the centre of the coil. Discuss the extent to which this experiment supports this suggestion.
You are to plan an investigation into the relationship between the frequency of vibration of a rubber cord and the tension in the cord when it is made to resonate. You are then to analyse a set of data from such an experiment.
(a) When a stationary (standing) wave in the fundamental mode is formed on a length l of rubber cord there is one antinode. Draw below the shape of this oscillation.
State the relationship between the wavelength λ of the wave and the length l between the supports.
(b) Stationary waves in a fixed length of a horizontal rubber cord under tension can be produced using a vibration transducer and a signal generator.
(i) Draw below a diagram of the experimental arrangement you would use to display such standing waves.
The following additional apparatus is available:
• slotted masses and hanger to provide the tension;
• pulley mounted on a clamp.
Mark on your diagram the fixed length l.
(3)
l
Mannan Waheed
Text Box
June 2008 (International)
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(ii) Describe the readings you would take to investigate the relationship betweenthe tension T in the cord and the fundamental resonant frequency f for a fixed length l.
A music amplifier can be thought of as a source of emf with an internal resistance. When such an amplifier is connected to a load resistance such as a loudspeaker, the power developed in the loudspeaker varies with the resistance of the loudspeaker. You are to plan an experiment to measure how the power varies with the resistance and then to analyse some data.
(a) (i) Explain why, when the switch is open, the reading on the voltmeter is very close to the emf E of the amplifier.
(iii) For a given value of R state an expression you would use to calculate the value of the current in the circuit. Hence show that the internal resistance r of the amplifier is given by.
(b) Describe how you would investigate how the power developed in the load varies with its resistance R. You should say what readings you would take and how you would obtain your values of the power.
You are to plan an experiment on a sample of gas using computer technology to capture the data. You will then analyse a set of data from a similar experiment.
(a) A sample of gas is held in a container at constant volume. The pressure of the gas is monitored by a pressure sensor mounted through the top of the container. The temperature of the gas is varied by placing the container in a water bath and the temperature of the bath is monitored by a temperature sensor. The output from each sensor is sent to a computer to record the data.
Draw a block diagram to show how the data is fed to the computer.
The temperature is to be varied from the ice point to the boiling point of the water.
How should the computer be used to record an appropriate set of data for this experiment?
You are to plan an experiment on a sample of gas using computer technology to capture the data. You will then analyse a set of data from a similar experiment.
(a) A calibrated syringe is filled with the gas at atmospheric pressure. The pressure of the gas is monitored by a pressure sensor attached to the end of the syringe. This sensor measures the difference between the pressure of the gas and atmospheric pressure. The output from this sensor is sent to a computer to record the data.
The block diagram for measuring and recording the pressure sensor is shown below:
The method is to vary the volume of the gas whilst keeping the temperature constant. The computer records the sensor reading. The volume of the gas is read from the scale on the syringe and the values are entered manually using the keyboard.
What must be done to avoid a systematic error in the pressure of the gas?
You are to plan an investigation of how the resistance of a thermistor varies with temperature. You are then to analyse a set of data from such an experiment.
(a) (i) Draw a diagram of the arrangement you would use to measure the resistance of a thermistor at different temperatures in the range 10 °C to 70 °C.
(3)
(ii) Describe how you would carry out the experiment and state any precautions that you would take to improve the accuracy of your results.
You are to plan an investigation of how the bending of a beam, when a mass is hung from the end of the beam, varies with the length of the beam. You are then to analyse a set of data from such an experiment.
(a) The beam, in the form of a wooden metre rule, is clamped over the end of a bench as shown below, with a 500 g mass suspended from its end.
It is suggested that the depression y of the end of the rule may vary with the horizontal distance x according to the equation
y = kxn
where k and n are constants.
The distance x is measured from the point at which the rule is clamped to the centre of gravity of the suspended mass.
Describe exactly how you would measure the quantities x and y. You may add to the diagram if you wish.
