Question

. HOTS
1. What is the angle of incidence of a ray if the reflected ray is at an angle of 90° to the incident ray?
2. Why is red light used as a traffic signal to stop vehicle?
3. A person whose retina is damaged is not able to see .Why?
4. What will you do to keep your eyes healthy?

Answer 1

1. Angle of incidence would be 45 degree as when reflected rays makes 90 degree with incident ray then it will make 45 degree with normal and so angle of reflection would be 45 degree. And since angle i is equal to angle r so angle of incidence is 45 degree

2.red light has longest wavelength and can be observed with much longer distance. So it is used in traffic signal so that far away vehicle should be conscious of the red light

3.A person with dead retina is not able to see because no image formation takes place as in our eyes image is formed on retina. Since no image is formed so no vision possible

4.we should have proper sites like having vitamin a and other supplements. Also washing eyes keeps the eyes healthy. Wearing sunglasses in sunlight also protects eyes. Wearing uv filteration glasses on watching TV also helps in protecting eyes. Maintaining a proper distance while reading and in good light helps in keeping long life of eyes

Answer 2

2: bcoz out of seven colours VIBGYOR Red colour disperse the least