An isolated metal sphere of radius $r$ has been charged so that the electric field strength at its surface is $E_0$. On Fig. 6.1, sketch the way the electric field strength $E$ varies with distance $x$ from the centre of the sphere. Your sketch should go from $x = 0$ to $x = 3r$.
A particle has de Broglie wavelength $\lambda_0$ when its momentum is $p_0$. On Fig. 6.2, sketch how the de Broglie wavelength $\lambda$ changes with momentum $p$ for momentum values from $\frac{p_0}{2}$ to $p_0$.
A radioactive isotope decays with half-life $15\,\text{s}$ to produce a stable product. At $t = 0$, 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 $t = 45\,\text{s}$.