(a)[1]
F is a focal point (principal focus) of the lens. Measure the focal length of the lens.
(b(i))[1]
From P, draw a line parallel to ST so that it meets AB at C. Label C.
(b(ii))[1]
Explain how you made sure that this line is parallel to ST.
(c)[1]
Draw a straight line from F through C and extend it until it meets the dotted line at R. Label R.
(d)[1]
Measure the angle $\theta$ between lines RC and CP.
(e)[1]
Determine $l$ in centimetres, where $l = \frac{2.2}{\sin \theta}$.
(f)[1]
Theory predicts that $l$ is the same as the distance CF. Measure CF and comment on how far your results agree with the theory.