How to Get Full Marks on Paper 2 Definition Questions?

State.  Describe.  Discuss.  Explain.  Show.  Suggest.

It is not always easy to earn full marks on questions that start with one of these command terms, so I’d like to share with you a step-by-step process that helped many of my students quickly improve on such questions:

1. Look at the number of marks, because these show you the number of key points you need to include in your answer.
2. Identify the topic where the question comes from.
3. Choose the key concepts that you will use. 
4. Write down your answer in the specific context of the question, using formulae where possible. 

Let’s see a couple of examples:

Example 1:

Question (May 2023, Paper 2, Timezone 2, SL Q3a/HL Q3a):

Blue light of wavelength is incident on a double slit. Light from the double slit falls on a screen. Explain the pattern seen on the screen.

[3 marks]

1. The question has 3 marks, so I will need 3 key points in my answer.
2. The topic must be waves, more specifically double-slit interference.
3. The key concepts here are: superposition, interference, path/phase difference, bright/dark fringes.
4. So my answer in the context of the question is:

• The light waves that emerge from the slits superpose (or interfere).
• When the light waves from the slits arrive in phase we have constructive interference, so a bright fringe is formed.
• When the light waves from the slits arrive 180 degrees out of phase we have constructive interference, so a dark fringe is formed.

Example 2:

Question (November 2020, Paper 2, SL Q1a(ii)/HL Q1a(ii)):

The rotating blades of a small aircraft exert a force on the surrounding air. The aircraft hovers motionless above the ground. Outline, by reference to Newton’s third law, how the upward lift force on the aircraft is achieved.

[2 marks]

1. The question has 2 marks, so I will need 2 key points in my answer.
2. This is Topic A, as they specifically ask me to use Newton’s third law.
3. The key concept here is basically given: Newton’s third law, which is, simply put, that “if object A exerts a force on object B, then object B must exert an equal and opposite force on object A”.
4. So my answer in the context of the question is:

• The aircraft blades exert a downward force on the air.
• Therefore, the air exerts an equal and opposite force on the aircraft blades.