AQA AS Physics

Topic Questions

1.2 Limitation of Physical Measurements

1a4 marks

Figure 1 shows the reading on a micrometer screw gauge.

Figure 1

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Determine the full reading on the micrometer with its absolute uncertainty.

 

1b3 marks

A student measures and records 10 repeat readings of the diameter of a wire using a micrometer screw gauge in mm shown in Table 1.

                              Table 1

1.24

1.23

1.25

1.19

1.20

1.22

1.24

1.20

1.23

1.19

 

Determine the mean diameter of the wire and its absolute uncertainty.
1c2 marks

Determine the percentage uncertainty in the result the student obtains for the diameter of the wire.

 Give your answer to an appropriate number of significant figures.

1d3 marks

For the experiment, the student requires the cross-sectional area of the wire.

Determine the cross-sectional area of the wire in mm2 and its percentage uncertainty.

  

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2a4 marks

Figure 1 shows the reading on a vernier calliper.

Figure 1

ZAWX4kON_1-2-s-q--q2a-medium-aqa-a-level-physics

Determine the full reading of the vernier calliper with its absolute uncertainty. 
2b3 marks

The reading from part (a) is taken after a mass has been added to a copper wire of length L and the wire extends.

 The original length of the wire L­ was 14.9 ± 0.05 mm.

Calculate the extension ∆L of the copper wire after the mass has been added with its absolute uncertainty.      
2c4 marks

Tensile strain is defined as the ratio between the extension of the wire and its original length.

Hence, or otherwise, determine the tensile strain of the copper wire and its percentage uncertainty.

 

2d1 mark

Suggest one way to improve the experiment to make the value of the wire extension more accurate.

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3a4 marks

A student participates in an experiment to measure the Earth’s gravitational field strength g. This is done using a simple pendulum.  

The student suggests the period of oscillation T is related to length of the pendulum L and by the equation:

             T = 2πsquare root of L over g end root

They measure length L to be 11.2 cm and measure the period T ten times. The results are recorded in Table 1

                          Table 1

0.67

0.66

0.67

0.68

0.69

0.64

0.66

0.65

0.68

0.65

Determine the mean period of oscillation and its percentage uncertainty.
   
3b1 mark

State one way the student could reduce the uncertainty in their value of T.

3c4 marks

The student estimates the uncertainty on the measurement of L to be ± 15 mm.

Hence, or otherwise, use your answer from part (b) to determine the percentage uncertainty in the value of g.

 

3d3 marks

Hence, or otherwise, use your answer from part (c) to determine the value and absolute uncertainty in the value of g.

Give your answer to an appropriate unit and number of significant figures.

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4a4 marks

Rearrange the following currents according to decreasing percentage uncertainty:

   4.1 ± 0.2 A,     5 ± 1 mA,        7.30 ± 0.23 A,      0.5 ± 0.05 mA

4b2 marks

A circuit is set up to measure the resistance R of a resistor. The potential difference (p.d) V across the resistor and the current I are measured.

 The readings for the p. d V and the corresponding current I are obtained. These are shown in Figure 1.

Figure 1

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Explain how Figure 1 indicates that the readings are subject to a systematic uncertainty and random uncertainties.

4c2 marks

State one way a systematic error could have occurred in this experiment and how this type of error can be fixed.

4d4 marks

In another experiment, the resistance of the resistor R is determined using the following data:     

         Current, I = 0.74 ± 0.01 A 

      Potential difference, V = 6.5 ± 0.2 V

Calculate the value of R, together with its percentage uncertainty. Give your answer to an appropriate number of significant figures.

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5a2 marks

A student has a diffraction grating that is marked 2.9 × 103 lines per m.

Calculate the percentage uncertainty in the number of lines per metre suggested by this marking. 

Give your answer to an appropriate number of significant figures.

5b3 marks

Determine the grating spacing and its absolute uncertainty in mm.

5c3 marks

Figure 1 shows part of another diffraction grating. A scale is given below.

Figure 1

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c)

Use Figure 1 to calculate the grating spacing of this diffraction grating. 

State an appropriate absolute uncertainty and calculate the percentage uncertainty.

5d1 mark

Hence, or otherwise, calculate the number of lines per metre on the grating.

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