Question

Which option below correctly compares the amount of radiation exposure from an annual dental X-ray and the radiation exposure from backgroundradiation during the same year?A. The dose from the dental X-ray is 8000 times smaller than theaverage annual dose of background radiation.B. The dose from the dental X-ray is 8000 times larger than theaverage annual dose of background radiation.C. The dose from the dental X-ray is 20 times larger than the averageannual dose of background radiation.D. The dose from the dental X-ray is 20 times smaller than theaverage annual dose of background radiation.

Answer 1

Choice A

Step-by-step explanation:

Let us go through each of the answer choices to see which one is correct.

A. The dose from the dental X-ray is 8000 times smaller than the average annual dose of background radiation.

This means

average annual dose of background radiation. = 8000* The dose from the dental X-ray

Now,

Average annual dose of background radiation = 4* 10^-4

and

The dose from the dental X-ray = 5* 10^-5

Therefore, we have

`4*10^(-4)=8000*5\cdot10^(-8)`

Is the above equation correct? We evaluate the right-hand side and see if it equals the left-hand side.

Now,

`8000*5\cdot10^(-8)=4*10^(-4)`

therefore,

`4*10^(-4)=4*10^(-4)`

Hence, choice A is the correct answer.