(a) the least scattered red colour reaching the eye
   (b) the dispersion of sun light occurred in air molecule in atmosphere
   (c) the diffraction of sunrays in atmospheric layers
   (d) interference of all the rays coming from the sun
Ans: (a)
191. The image of an object formed on the retina of the eye is
   (a) virtual and upright
   (b) virtual and inverted
   (c) real and inverted
   (d) real and upright
Ans: (c)
192. When one enters a dark room after being in bright light one is not able to
   see anything clearly for a while because
   (a) the retina of the eye moves forward
   (b) the retina of the eye moves backward
   (c) c).the iris is unable to dilate the pupil immediately to be able to see things
   (d) the eye has no power of accommodation
Ans: (c)
193. Astigmatism, a structural defect of the eye, is due to
   (a) the eye lens being thin
   (b) the eye lens being thick
   (c) lack of symmetry in the curvature of the eye preventing rays of light from
       being brought to a common focus
   (d) the pupil being very small
Ans: (c)
194. Some persons are not able to see distant objects clearly because the image
   of the object is focused in front of the retina. This defect is known as
   (a) short sight
   (b) long sight
   (c) astigmatism
   (d) presbyopia
Ans: (a)