Help.. How long will it take three quarters of a sample of a radioactive
element to decay if its half-life is 4 days?
a. 2 days
b. 3 days
c. 4 days
d. 8 days

the correct answer to this question is #5

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.

i think the answer is c hope this