Question

 A householder is worried about the radiation emitted by the granite worktop in his kitchen.

1 kg of granite has an activity of 1250 Bq. The kitchen worktop has a mass of 180 kg.

Calculate the activity of the kitchen worktop in Bq.

Answer 1

The activity is an additive quantity. If 1 kg of granite has an activity of 1250 Bq, then 180 kg will have the following activity:

$$A = 180kg\times1250\dfrac{Bq}{kg} = 2.25\times 10^5Bq$$

Answer. $2.25\times 10^5Bq$.