# If you get these answers in your IB Physics exams - they’re wrong!

## I always say to students that nothing is impossible, but actually, in Physics somethings ARE impossible.

I've been helping IB Physics students to be more strategic about their exam performance since 2004.

If you’re completing a “calculate” question in your IB physics exams and, for example, you get the answer of 4×10^{8} ms^{-1}, it’s incorrect. It’s clearly wrong.

**Know what’s IMPOSSIBLE to get better marks. **

Another example would be if you calculate the refractive index of glass to be n=10.45. That’s clearly incorrect. We *know* the refractive index of optically active substances tends to be in the region 1<n>2.5.

**It’s really important that you understand and have an idea of what is reasonable and conduct a reasonableness check at the end of every “calculate” question. **

If I calculate the mass of a car to be 20,000kg, I know the answer is incorrect because I have an understanding that the mass of a car is around about 1000kg. Being able to estimate and evaluate answers like this in your head can help you conduct a reasonable check at the end of your “calculation” questions.

Lots of students make this mistake, they don’t do reasonableness checks and end up losing marks. Don’t be that student!

*Don’t make mistakes that can be easily rectified!*

### MORE HELP WITH IB PHYSICS

- For a longer discussion 5 mistakes students make in their IB Physics exams - click here
- Click here for my 'How to Study IB Physics' Guide to help you organise your study and learn more exam tips and tricks for IB Physics