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

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

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

If you’re completing a “calculate” question in your IB physics exams and, for example, you get the answer of 4×10^8 m/s, 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