(i) The image of a candle flame placed at a distance of 36 cm from a spherical lens, is formed on a screen placed at a distance of 72 cm from the lens. Calculate the focal length of the lens and its power.

(ii) Below is an incomplete table showing the arrangement of electromagnetic spectrum in the increasing order of their wavelength. Complete the table.



(a) Identify the radiation A.
(b) Name the radiation used to detect fracture in bones.
(c) Name one property common to both A and Radio waves.

(iii) (a) Why do we use red colour as a danger signal on the top of a skyscraper?
(b) The diagram below shows the path of a blue ray through the prism:



1. Calculate the critical angle of the material of the prism for blue colour.
2. What is the measure of the angle of this prism (A)?
3. Which colour should replace the blue ray, for the ray to undergo Total Internal Reflection?

Solution

,,