What is an astronomical unit or AU? A)

A unit of time equal to one light year or 6 trillion miles.

B)

A unit of distance equal to the average distance from Earth to the Suntor

93 million miles.

A unit of distance equal to the size of the Milky Way Galaxy or 100,000

light years across

D)

A unit of time that is equal to the amount of time it takes light to travel

from the Sun to Earth,

B

Explanation:

The correct option should be B.

The Astronomical Unit, AU, is a measurement unit for length in general astronomy and represents the mean or the average distance of the sun from the earth.

Mathematically, in astronomy,

1 astronomical unit = 150,000,000 km

But then, 1 km = 0.621371 mile

Hence,

150,000,000 km = 150,000,000 x 0.621371 miles

            ≈93,000,000 miles

Therefore, 1 astronomical unit can also said to be approximately equal to 93,000,000 miles.

The correct option is B

one part of the electromagnetic spectrum that arrives on earth as solar radiation from the sun is the visible spectrum. wavelengths of the visible spectrum combine to form what we refer to as

answer - d) ultraviolet radiation.

violet /   380–450 nm / 668–789 thz

violet is number 1 in the chart of visible light.