An isolated metal sphere of radius $r$ carries charge so that the electric field strength at its surface is $E_0$. On Fig. 6.1, sketch how the electric field strength $E$ changes with distance $x$ from the centre of the sphere. Your sketch should run from $x = 0$ to $x = 3r$.
The de Broglie wavelength of a particle is $\lambda_0$ when its momentum is $p_0$. On Fig. 6.2, sketch how the de Broglie wavelength $\lambda$ of the particle varies with momentum $p$ for momentum values from $\frac{p_0}{2}$ to $p_0$.
A radioactive isotope has a half-life of $15\,\text{s}$ and decays to a stable product. At time $t = 0$, a fresh sample of the radioactive isotope contains $N_0$ nuclei and no nuclei of the stable product. On Fig. 6.3, sketch how the number $n$ of nuclei of the stable product varies with $t$ from $t = 0$ to $t = 45\,\text{s}$.