CAIE A-Level Physics A2 23.2.5.0.693 T 1 2

[Maximum number: 2]

Polonium-211 $\left({ }_{84}^{211} \mathrm{Po}\right)$ decays by alpha emission to form a stable isotope of lead (Pb).

The variation with time t of the number of unstable nuclei N in a sample of polonium-211 is shown in Fig. 9.1.

Fig. 9.1

At time t=0, the sample contains only polonium-211.

Use Fig. 9.1 to determine the decay constant $\lambda$ of polonium-211. Give a unit with your answer.
$\lambda=\ldots \ldots \ldots \ldots \ldots . \ldots \ldots . . . . . . . . .$ . unit ..................

(half-life found as) 0.52 s or correctly read points substituted into
$N=N_{0} e^{-\lambda t}$ $\lambda=\frac{0.693}{t_{1 / 2}}$ $\lambda=\frac{0.693}{0.52}$ $\lambda=1.3 \mathbf{~ s}^{-1}$

All question bank results loaded

CAIE A-Level Physics A2 23.2.5.0.693 T 1 2 Topic Practice

Question 1