Understanding Light, Lenses, and Mirrors: Final Exam Review

[dranseth]

Homework Statement

I have a final tomorrow, and I there are a couple questions that I don't know.

When the angle of incidence is the critical angle, the angle of refraction will be?

If a screen is moved 3 times the distance from a light source, what will the intensity on the screen be reduced to?

A ray of light is incident at 38º on a curved mirror. At what angle will the reflected ray leave the mirror?

Homework Equations

n1sin90º=n2sin(critical angle)
I'm not sure which formula to use for the one regarding light intensity, and for the last, I drew it out.

 

[Leong]

90 degree [according to the definition of critical incident angle]

2. don't know

3. 38 degree [ according to the laws of reflection of light: the reflected angle is equal to the incident angle]

 

[Moetasim]

I can provide some guidance and information to help you approach these questions. First, it is important to understand the concepts of light, lenses, and mirrors. Light is a form of electromagnetic radiation that travels in waves and can be seen by the human eye. Lenses are transparent objects that can refract (bend) light, and mirrors are smooth surfaces that can reflect light.

Now, let's address the questions. When the angle of incidence is the critical angle, the angle of refraction will be 90º. This means that the light ray will not refract and will instead be reflected back into the same medium.

To calculate the intensity of light at a certain distance, you can use the inverse square law, which states that the intensity of light is inversely proportional to the square of the distance from the source. In this case, if the distance is tripled, the intensity will be reduced by a factor of 9 (3^2 = 9).

For the last question, you can use the law of reflection, which states that the angle of incidence is equal to the angle of reflection. In this case, the reflected ray will leave the mirror at an angle of 38º.

I hope this helps you approach your final tomorrow with a better understanding of these concepts. Remember to use the appropriate equations and always double check your calculations. Good luck!