Yang can focus on objects 150 cm away with a relaxed eye. With full accommodation, she can focus on objects 20 cm away. After her eyesight is corrected for distance vision, what will her near point be while wearing her glasses?

Explanation:

Without wearing glasses , her near point is 20 cm .

for correction of eye

u = infinity ,

v = - 150 cm

f = ?

f = - 150 cm

He must be wearing glass of focal length of 150 cm .

If near point be x after wearing glass ,

u = x

v = - 20 cm

f = - 150 cm

x = 23 cm .

pe = weightxheight = 2000x1000=2,000,000joules