OCR A Level Physics Data Sheet

How do I use the OCR Data, Formulae and Relationships Booklet?

You have no doubt invested a lot of time into learning the content, skills and different types of questions for your exams. You would be selling yourself short by not familiarising yourself with the Data, Formulae and Relationships Booklet as well.

This booklet has 7 pages of information, which may seem intimidating, but everything is there for a reason. This information is split up into sections

• The data section, which consists of:

  • Physical constants

  • Quark charges

  • Conversion factors

  • Mathematical equations

• The formulae and relationships section. 

Physical Constants and Quark Charges

When using formulae (from the Formulae and Relationships section) in your exam, many of these will include constants such as Planck’s constant, the magnitude of charge on an electron or the gravitational constant. These are listed in this part of the booklet. 

Source: OCR Website

Another really useful (and less obvious) feature of this section is the units of these constants. So many students lose marks to the use of incorrect units in questions - we’ve all accidentally left a mass in grams instead of kilograms, or a temperature in degrees Celsius instead of Kelvin. 

However, if you are using an equation involving one of these constants, then the units of every other quantity in the question must match the units of the constant. 

For example, imagine you need to calculate a force between two stars, but have been given masses in solar masses and the distance in light years. If you look at the units of the gravitational constant G (which features in the equation for gravitational force), these are N m2 kg−2. Your distances need to be in metres and masses in kilograms to use this constant. Your answer for force will then be in units.

Conversion Factors

Following on from the example above, converting units is not always a simple task. This section lists some common conversions between different units for the same quantity. 

Source: OCR Website

There are many different ways of using these conversion factors, but often the best way is to just treat them like any other equation. 

To convert 1.80 × 10−18 J to eV, for example, start by writing out the conversion factor. 

To find the number of electronvolts in 1.80 × 10−18 J, divide the quantity by 1 eV. The conversion factor tells us that we just need to divide by 1.60 × 10−19 J. 

It’s as simple as that - this tells us that there are 11.25 electronvolts in 1.80 × 10−18 J. Don’t forget to write out the answer in full.

Mathematical Equations

This is a list of all the equations that, while not physics-specific, will really help you out in those more complex calculation questions. Finding the surface area of a sphere or the volume of a cylinder always catches students out as the equations look quite similar. 

Source: OCR Website

It can be tricky to remember things like small angle approximations in the diffraction topic, or the logarithm identities that pop up in radioactive decay, luckily you don’t have to! 

If maths is the language of physics then this section is your handy travel translation guide. Many of the harder questions in exams require you to perform complex calculations or use the geometry of a system to answer the question, so this section is a real life-saver for those scenarios. 

Knowing the Contents of the Booklet

Now the whole point of this booklet is to avoid you memorising every equation and constant in your syllabus. That being said, it's not going to be much use if you don't know what's actually included in the booklet.

By being aware of its contents, when you come to that tricky pressure question with irregular surface areas, or have to find an angle in a diffraction question, you will know to pick up that booklet and check whether any of the identities in the Mathematical Equations section can help you. 

So, the next time you go through some practice questions, try printing out the data booklet and keep it on your desk to get you into the habit of using it. By minimising the number of unfamiliar things in your exam, you are maximising your chance of getting yourself the very best results.