Question

If a sample emits 2000 counts per second when the detector is 1 meter from the sample, how many counts per second would be observed when the detector is 3 meters from the sample?

Using the sample in above question how many counts per second would be observed when the detector is 10 meters away from the sample?

Answer 1

At 3 meter distance, the per-second count is 222.22 and at a 10 meter distance, the per-second count is 20.

Step-by-step explanation:

The number of particles (N) counts are inversely proportional to the distance between the source and the detector.

By using the below formula we can find the number of counts.

`N2 = ((D1)^2)/((D2)^2) * N1 \\N1 = 2000 \\D 1 = 1 \ meter \\D2 = 3 \\`

The number of count per second, when the distance is 3 meters.

`= (1)/(3^2) * 2000 \\= 222.22`

Number of count per second when the distance is 10 meters.

`= (1)/(10^2) * 2000 \\= 20`