Question

(trig based physics) Please explain what is happening, I am trying to LEARN how to do these problems as well!

Ignore air resistance and gravity in all questions.

1. When Hydrogen is heated on earth, it emits 4 colours of visible light of wavelengths 410 nm, 434 nm, 486 nm and 656 nm. When Hydrogen on a distant galaxy is observed, the 410 nm light appears to have a wavelength of 409 nm.

1. a) Is the galaxy moving towards earth or away from it? Explain.

2. b) Find the relative velocity of the galaxy with respect to the observer on earth. [Note: For this question, maintain a lot of accuracy by carrying a lot of digits in your calculations.]

3. c) Find the observed wavelengths of these other wavelengths of light originating from that galaxy.

2. A convex mirror has a radius of curvature of 4 m. A boy stands in front of the mirror so that he appears 3 times shorter than his actual height. If the image is upright, how far is he standing from the mirror? Explain if the image is real or virtual.

3. An object is placed 4 cm away from a concave lens of focal length 3 cm. A convex lens of focal length 5 cm is placed 4 cm away from the concave lens in the same direction (so the distance between convex lens and the object is 8 cm). Use any method to figure out if the final image is real/virtual, upright/inverted and find its distance from the convex lens.

4. Draw proper ray diagrams for questions 2 and 3.

Answer 1