Nature of light exam paper

42 marks – 1 hour


Question 1.

  1. Calculate the colour of light used in the double slit experiment if you were 1m from the wall and the distance between the 0th maxima and the 3rd maxima was 0.02025 m. You used a double slit with 100 um gap. [4 marks]
  2. If the expected value was 680 nm, calculate the percentage error. [1 mark]

Question 2.

  1. Draw a scientific diagram of the experimental procedure used for the double slit experiment [3 marks]
  2. Assess the validity and reliability of the experimental process [4 marks]
  3. Explain how you could increase the reliability of this experiment [2 marks]

Question 3.

Two students are having a heated debate over accuracy and precision for the refraction grating experiment. One student wants to increase the distance between the diffraction grating and the wall to increase the precision of the experiment. However, the other student argues the precision is only changed by the equipment. Explain, using a diagram, who is correct. [4 marks]

Question 4.

  1. Compare and contrast, with reference to the model of the atom, an absorption and emission spectra of the discharge tube containing hydrogen gas. [4 marks]
  2. Why are there multiple bands in a Hydrogen spectra despite there only being one electron. [2 marks]

Question 5.

  1. Label the nodes, antinodes and regions of maximum and minimum interference on the following diagram. [2 mark]

b) Explain why the double slit experiment creates the interference pattern that is observed. [2 marks]

Question 6. 

Compare and contrast the spacing between local maxima of a diffraction grating and  a double slit if they both have the same distance between slits [4 marks]

If you are feeling adventurous…

Question 7.

A bright science student wants to make the diffraction grating experiment more advanced. So he uses a helium discharge tube as his light source, focusing the emitted light with a magnifying lens so it hits the diffraction grating. Explain how this light is excited and what the spectra of this would look like. [5 marks]

Question 8.

In the experiment, the student forgot to measure the distance between maxima 0 and maxima 2. They were passing the light between a 100um double slit, 1 m from the wall. However, they did measure distance between maxima 0 to maxima 1 and 3 being 0.0071m and 0.025m respectively. What do you expect the measured distance between maxima 1 and 2. [5 mark extension]


  1. A 676 nm B 0.6%


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