Give an example of an uncontrolled chain reaction.

Copy and complete the following nuclear equations by filling in the correct values of atomic and mass numbers for $P_{1,} P_2$ and $P_3$.

${{}_{92}P}^{238} \stackrel{\alpha }{\to }$$P_1 \stackrel{\beta }{\to }$$P_2 \stackrel{\beta }{\to }$$P_3.$

Draw a cathode ray tube consisting of a heater, a cathode, a cylindrical anode and a defecting system. Show how you will connect a low tension battery of $6 \mathrm{V}$ and a high tension battery of $1000 \mathrm{V}$to the cathodes of the tube.