K.C.S.E Physics Q & A - MODEL 2018PP2QN17

K.C.S.E Physics Q & A - MODEL 2018PP2QN17

​(a) Water waves from a certain Source move from the shallow end to the deep end. State the change that occurs at the deep end on the following:
(i) Frequency 
(ii) Wavelength 
(iii) Velocity 

​(b) (i) A biconvex lens forms an upright image twice the size of the object. If the focal length of the lens is 20cm, determine the object distance. 
(ii) State two optical instruments which produce a magnified real image using a Convex lens. 
(c) State one difference between the working of the human eye and the lens of a camera. 
(d) A lens of focal length 2Ocm forms a virtual image when an object is placed 60cm from the lens. State with a reason the type of lens used.

answers

(a)(i) No change in frequency
(ii) Wavelength increases
(iii) Velocity increases

(ii) a film projector
A compound microscope
(c) In a camera focusing is done by changing the distance between the lens and the film. While in the eye focusing is done by changing the curvature of the lens.
d) Diverging lens 
Forms a virtual image when the object distance is greater than the focal length.