Watching TV With Your Neck in a Plaster Cast.

Most recent answer: 11/04/2011

Q:
Please tell me what kind of prism I would need to make "spectacles" to enable me to watch TV at the end of my bed without bending my neck (which is in a plaster cast). Thank you
- Heve (age 16)
Dublin, Ireland
A:
If you put a plain mirror above you at a 45o angle you could see the TV.   Unfortunately the image would be upside down.   What you need is a penta-prism which has two reflecting surfaces which cancel the two inversions out.

LeeH

(published on 11/04/2011)