In order to assess these abilities and skills, a number of different types of questionare used.
In AS Level Physics unit tests, these include short-answer questions, structured questions requiring both short answers and more extended answers, together with free-response and open-ended questions. Multiple choice question papers are not used, although it is possible that some short-answer questions will use a multiple choice format, where you have to choose the correct response from a number of given alternatives.
A short-answer question may test recall or it may test understanding by requiring you to undertake a short, one–stage calculation. Short-answer questions normally have space for the answers printed on the question paper. Here are some examples (the answers are shown in blue):
What is the relationship between electric current and charge flow?
Current = rate of flow of charge.
The current passing in a heater is 6 A when it operates from 240 V mains. Calculate the power of the heating element.
P = I x V = 6 A x 240 V = 1440 W
Which of the following is the correct unit of acceleration?
Structured questions are in several parts. The parts are usually about a common context and they often become progressively more difficult and more demanding as you work your way through the question. They may start with simple recall, then test understanding of a familiar or an unfamiliar situation. The most difficult part of a structured question is usually at the end, where the candidate is sometimes asked to suggest a reason for a particular phenomenon or social implication. Most of the practice questions in this book are structured questions, as this is the main type of question used in the assessment of AS Level Physics.
When answering structured questions, do not feel that you have to complete one question before starting the next. The further you are into a question, the more difficult the marks are to obtain. If you run out of ideas, go on to the next question.
Five minutes spent on the beginning of that question are likely to be much more fruitful than the same time spent wracking your brains trying to think of an explanation for an unfamiliar phenomenon.
Here is an example of a structured question that becomes progressively more demanding.
(a) A car speeds up from 20 m/s to 50 m/s in 15 s.Calculate the acceleration of the car.
acceleration = increase in velocity ÷ time taken
= 30 m/s ÷ 15 s = 2 m/s2
(b) The total mass of the car and contents is 950 kg. Calculate the size of the unbalanced force required to cause this acceleration.
force = mass x acceleration
= 950 kg x 2 m/s2 = 1900 N
(c) Suggest why the size of the driving force acting on the car needs to be greater than the answer to (b)
The driving force also has to do work to overcome the resistive forces, e.g. air resistance and rolling resistance.
In AS Level Physics, questions requiring more extended answers will usually form part of structured questions. They will normally appear at the end of structured questions and be characterised by having at least three marks (and often more, typically five) allocated to the answers as well as several lines (up to ten) of answer space. These questions are also used to assess your abilities to communicate ideas and put together a logical argument.
The correct answers to extended questions are less well-defined than to those requiring short answers. Examiners may have a list of points for which credit is awarded up to the maximum for the question, or they may first of all judge the quality of your response as poor, satisfactory or good before allocating it a mark within a range that corresponds to that quality.
As an example of a question that requires an extended answer, a structured question on the use of solar energy could end with the following:
Suggest why very few buildings make use of solar energy in this country compared to countries in southern Europe. 
Points that the examiners might look for include:
- the energy from the Sun is unreliable due to cloud cover
- the intensity of the Sun’s radiation is less in this country than in southern Europe due to the Earth’s curvature
- more energy is absorbed by the atmosphere as the radiation has a greater depth of atmosphere to travel through
- fossil fuels are in abundant supply and relatively cheap
- the capital cost is high, giving a long payback time
- photo-voltaic cells have a low efficiency
- the energy is difficult to store for the times when it is needed the most
Full marks would be awarded for an argument that put forward three or four of these points in a clear and logical way.
Little use is made of free-response and open-ended questions in AS Level Physics. These types of question allow you to choose the context and to develop your own ideas. Examples could include ‘Describe a laboratory method of determining g, the value of free-fall acceleration’ and ‘Outline the evidence that suggests that light has a wave-like behaviour’. When answering this type of question it is important to plan your response and present your answer in a logical order.