(a(i))[1]
State two differences between the object and the image.
(a(ii))[1]
Measure the height $h_o$ of the object, then measure the height $h_i$ of the image.
(b)[1]
Calculate the image magnification $m$ from the equation $m = \frac{h_i}{h_o}$.
(c)[1]
Calculate the focal length $f$ of the lens from the equation $f = \frac{mu}{(1 + m)}$ where $u = 20.0\,\text{cm}$.