Short Question Answers
1. State the factors on which the deviation produced by a prism depend.
The deviation produced by the prism depends upon;
- Angle of prism
- Refractive index of a medium
- Angle of incidence
- Color of the light and
- Material used to make prism.
2. What are the advantages of total reflecting prism over the plane mirror?
The advantages of total reflecting prism over plane mirror are as follows;
- The intensity of reflected light is more in prism than that of light reflected from the plane mirror because When a light is reflected from total reflecting prism, whole of the light is totally internally reflected but from plane mirror 90% are only reflected.
- The image is not laterally inverted in case of total reflecting prism as in plane mirror
- No multiple reflection takes place in Reflecting prism like that of plane mirror.
- It doesn’t require silvering for reflection whereas plane mirror requires.
- Use of total reflecting prism reduces the size of optical instrument than in using plane mirror.
3. Under what conditions does a prism produce the angle of minimum deviation?
When the angle of incidence is equal to angle of emergence and the angle of refractions at the two sides are equal then the prism produces minimum deviation.
4. A glass prism is immersed in water. What happens to the value of angle of minimum deviation?
The refractive index (µ) of a glass prism with angle (A) and minimum deviation (δmin) are related by a formula,
µ = sin ((δmin + A)/ 2) / sin(A/2)
Therefore, when the glass prism is immersed in water the refractive index decreases which result to decrease in angle of minimum deviation.
Share on Social Media