2.DVD players use red lasers with a wavelength of 650 nm, while Blu-ray players use blue lasers (hence the name) with a wavelength of 405 nm.
1. Which color would need a larger double slit spacing d to produce an interference pattern that has the first maxima 1 mm from the central bright spot?

Blue light

Explanation:

For maxima interference we have the relation

where

m =  order

d = Slit gap

we have the relation

y = First maxima =  1 mm (fixed)

D = Distance to screen = 1 m (fixed)

So, the wavelength needed should be larger.

Hence, the blue light which has higher wavelength of 650 nm is to be used as it requires larger double slit spacing.

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.