K.C.S.E Physics Q & A - MODEL 2019PP2QN17

K.C.S.E Physics Q & A - MODEL 2019PP2QN17

(a) Figure 10 shows a ray of light travelling from glass to air.

​Determine the:
(i) critical angle of the glass — air interface 
(ii) refractive index of glass 
(b) Apiece of metal is embedded at the centre of an ice block 15cm from the surface of the ice. Given that the refractive index of ice is 1.32, determine how far from the surface of the ice block the metal appears to be. 
(c) Figure 11 shows, two  rays of incident on a diverging lens.

Complete the  ray diagram to show the path of the rays after passing through the lens.
(d) (i) State two differences between the human eye and a camera lens. 
(ii) State the name of the part of the eye that enable the lens to focus images of objects at different distances. ​

ANSWERS

​(d)(i) Eye has a variable focal length whole the focal length of camera lens is fixed
 Image distance from the lens is almost constant in the eye while in a camera it can be varied
Eye lens is muscle while glass/clear plastic
(ii) Ciliary muscles