1. If a radioactive sample has an initial count rate of 600 Bq. What is its count rate after
i) l half-life?
ii) 2 half-lives
iii) 3 half-lives
iv) 4 half-lives?

See explanation

Explanation:

Since the original count rate is 600 Bq,

i) after 1 half life, the count rate decreases to 1/2 of 600 Bq = 300 Bq

ii) after 2 half lives, the count rate decreases to 1/4 of 600 = 150 Bq

iii) after 3 half lives, the count rate decreases to 1/6 of 600 = 100 Bq

iv) after 4 half lives, the count rate decreases to 1/8 of 600 = 75 Bq

here we know that ball will drop down by total distance 3.2 m

so here we know that

now using kinematics

now in the same time it will cover horizontal distance of 0.75 m

so speed of the ball will be