Question

The given figure shows a mixed source R of $\alpha -and\beta -particles$ in a thick lead container. The particles pass through a magnetic field in a direction perpendicular to the place of paper inwards as shown by $\times$.
(a) State and show in the diagram how the particles get affected.
(b) Why is the source R kept in a thick lead container? [5 MARKS]

Answer 1

Each Part: 2.5 Marks

(a) The complete diagram is shown below. The component which is deflected towards the left consists of positively charged particles while the one which is deflected towards the right consists of negatively charged particles recognised as $\alpha -particlesand\beta -particles$ respectively. The third component, i.e. $\gamma -ray$ remains undeflected showing no charge on it.

(b) R is a radioactive substance. For a radioactive substance, a container should be such that it can absorb the radiations which strike on its walls. Out of $\alpha ,\beta$ and $\gamma$ radiations, $\gamma$ - radiations need very thick lead sheets. That is why R is kept in a thick lead container.