QUESTION 1 i. Using a protractor, measure the angle of incidence for the ray travelling along XA and hence, calculate the angle of refraction in the glass. A motorist pays for petrol at a filling station using a bank card for which a personal identification number Refractive index of glass = 1.5 must be entered on a keypad. There is a thick sheet of glass between the cashier and the motorist, with a gap at the bottom to give to the key glass security barrier key pad Angle of refraction = i. Add to the diagram to show that light travelling initially along the path XA does not reach the eye of the motorist. You will need to use a protractor to help you. When standing as shown in the diagram above, refraction of light through the glass means that the motorist is unable to see the keypad without moving his head to see under the glass. glass barrier eve key pad The diagram above shows rays from the keypad. The light travelling initially along the path XA, which then passes through the glass, does not reach the motorist's eye. Assume no light passes through the surface AB