# Optics : White light incident on water drop

1. Jul 7, 2017

### Jahnavi

1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

I know that if white light is incident on a triangular prism , then lights of different wavelengths are deviated by different amounts and dispersion occurs .

But I am not sure what would happen in this case where we have a spherical drop .

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2. Jul 7, 2017

### haruspex

What law determines the deviation?

3. Jul 7, 2017

### Jahnavi

Snell's law .

OK . I got your point . But what if the incident ray is at some angle to horizontal ?

Last edited: Jul 7, 2017
4. Jul 7, 2017

### sanujan

A is correct answer. if it the spherical considered as regular.if it is not the answer be B.

5. Jul 7, 2017

### sanujan

nothing law is necessary for determining the deviation.

6. Jul 7, 2017

7. Jul 7, 2017

### sanujan

draw perpendicular line for the circle it will goes through the radius of the circle and the normal also in the line of radius.and the light incident on spherical through radius.
i think u know that any of light ray do not deflect when incident through normal line

8. Jul 7, 2017

### Jahnavi

What do you mean by above ?

9. Jul 7, 2017

### Jahnavi

@haruspex , what would happen if ray is incident at some angle ?

10. Jul 7, 2017

### sanujan

If the rain drop is regularly spherical then there is no colour dispersion occur.

11. Jul 7, 2017

### haruspex

Do you mean, at some angle to the normal? Then there would be deviation, dispersion, and maybe internal reflection.

12. Jul 7, 2017

### sanujan

Reflect on the first surface
Emerges from the other surface
Note that a partial reflection also takes place on the surfaces

13. Jul 7, 2017

### haruspex

Yes, but I don't think that is what B is referring to.

14. Jul 7, 2017

### haruspex

Snell's law gives the answer. It might or might not be necessary to appeal to that.

15. Jul 7, 2017

### sanujan

In a water drop there is no full molecules or full of space