The half lives of 2 radioactive specimen are $T_1=5$ years. and $T_2=7.5$ years. The ratio of their disintegration constants $λ_1$ and $λ_2$ is:

$\frac{3}{2}$ $\frac{2}{3}$ 1 : 1 0.693

$\frac{3}{2}$

The correct answer is Option (1) → $\frac{3}{2}$