You are Here: Home >< Physics

# Gsce ISA- refraction watch

1. Hi everyone

I've got the experiment for my physics 3 coursework and it's to do with refraction and i'm quite confused on the topic.

If you're measuring the angle of incidence of the air to the perspex and then measuring the angle of refraction- should this angle be bigger or smaller due to the increased density of the Perspex box compared to the air??-----> hope this makes sense

And also why does when shining the light from the ray box at the Perspex box at 90degrees then why does the light continue straight instead of refracting??

Thanks and I appreciate all the help that anyone can give xxx
2. (Original post by Cait123)
Hi everyone

If you're measuring the angle of incidence of the air to the perspex and then measuring the angle of refraction- should this angle be bigger or smaller due to the increased density of the Perspex box compared to the air??-----> hope this makes sense

And also why does when shining the light from the ray box at the Perspex box at 90degrees then why does the light continue straight instead of refracting??
When light travels from a less dense medium to a more dense medium, the angle of incidence > angle of refraction.

Remember that these angles are measured from the normal? If the light is travelling at 90 deg from the surface, the angle from the normal, angle of incidence, is 0 deg. As angle of incidence > angle of refraction, nothing is greater than 0, the angle of refraction must be 0 deg too. That is to say the light continues to travel straight in the path of the normal to the surface.

There is still one thing I'm confused at and it may seem really stupid- but I'm struggling at how to measure these angles with a protractor... I don't know if you could try and explain it but I know it might be too difficult to do without a form of visual aid.

And also will the angle of incidence be opposite to angle of refraction??

Thanks soooooooo much!! Much love
Xxx
4. (Original post by Cait123)

There is still one thing I'm confused at and it may seem really stupid- but I'm struggling at how to measure these angles with a protractor... I don't know if you could try and explain it but I know it might be too difficult to do without a form of visual aid.

And also will the angle of incidence be opposite to angle of refraction??

Thanks soooooooo much!! Much love
Xxx
Place the line labelled 0 deg on either the light ray or the normal. Look for the other line above the normal, if you let the line labelled 0 deg be on top of the light ray and then just read the angle!

Yeah, the angles of incidence and refraction are always opposite of each other.

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: October 2, 2011
Today on TSR

### Cambridge interviews

Find out who is getting invitations

### University open days

• University of Roehampton
Sat, 17 Nov '18
• Edge Hill University
Faculty of Health and Social Care Undergraduate
Sat, 17 Nov '18
• Bournemouth University