# How Many HVLs Are Needed to Reduce Beam Intensity?

## Question:

How many HVLs are needed to reduce beam intensity from 600 mR to 300 mR?

A. One HVL B. Three HVLs C. Four HVLs

## Answer:

Three HVLs are needed to reduce the beam intensity from 600 mR to 300 mR.

## Explanation:

In radiation physics, HVL stands for Half-Value Layer, which is a measure of the thickness of a material required to reduce the intensity of a beam of radiation by half.

To reduce the beam intensity from 600 mR (milliroentgens) to 300 mR, we need to find how many HVLs are required.

Since each HVL reduces the intensity by half, we can calculate the number of HVLs needed by dividing the initial intensity by the desired final intensity:

600 mR / 2 = 300 mR (1 HVL)

300 mR / 2 = 150 mR (2 HVLs)

150 mR / 2 = 75 mR (3 HVLs)

Therefore, three HVLs are needed to reduce the beam intensity from 600 mR to 300 mR.