x Turn on thread page Beta
 You are Here: Home >< Physics

# physics p3 help watch

1. In the aqa textbook theres some question on lenses like: a converging lens produces a magnification of x2 when it is used to form a real image that is a distance of 8cm from the object A) Draw a scale ray diagram of 8cm from the object B) Use your diagram to find the focal length of the lens

I've been trying for hours to work out how to do this but can't Could someone please show me how thanks!
2. (Original post by C-king)
In the aqa textbook theres some question on lenses like: a converging lens produces a magnification of x2 when it is used to form a real image that is a distance of 8cm from the object A) Draw a scale ray diagram of 8cm from the object B) Use your diagram to find the focal length of the lens

I've been trying for hours to work out how to do this but can't Could someone please show me how thanks!
We can't teach you how to draw ray diagrams here. I assume you have done this in class.
Regarding this particular question, you need to remember that magnification is also given by image distance divided by object distance.
If the magnification is x2 then if the image distance is 8cm what is the object distance?
After that you draw the standard ray diagram with the image and object distances now known. You can also calculate the focal length to check your answer by using the lens formula.

http://www.physics-chemistry-interac...x_positive.htm
3. When you say image distance, do you mean from the lens? When you say image distance what is it from?

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: April 12, 2013
Today on TSR

### Happy St Patrick's day!

How are you celebrating?

### Stay at sixth form or go to college?

Discussions on TSR

• Latest
Poll
Discussions on TSR

• Latest

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE