The half-life period of is 5760 year

PHYSICS · Subjective · A Level · Physics · Nuclear physics · Nuclear physics

Problem

The half-life period of

\text{C}^{14}

is 5760 year. A piece of wood when buried in the earth had 1%

\text{C}^{14}

. Now as charcoal it has only 0.25%

\text{C}^{14}

. How long has the piece of wood been buried?