During world war ii, tritium (3h) was a component of fluorescent watch dials and hands. assume you have such a watch that was made in january 1944. if 16% or more of the original tritium was needed to read the dial in dark places, until what year could you read the time at night? (for 3h, t1/2 = 12.3 yr.)

1976

Explanation:

The first order decay of tritium can be represented through the following expression.

where,

[H]t is the concentration of tritium after a time t has elapsed

[H]₀ is the initial concentration of tritium

k is the rate constant

Given the half-life (t1/2) is 12.3 years, we can calculate the rate constant using the following expression.

The concentration of tritium at certain time is 16% of the initial concentration, that is, [H]t = 0.16 [H]₀.

If the watch was made in 1944, you could read the time until 1944 + 32 = 1976.