A machinist with normal vision has a near point at 25 cm. This machinist wears +4.25-diopter eyeglasses in order to do very close work. With these eyeglasses, what is the near point of the machinist? a. 12 cm
b. 10 cm
c. 7 cm
d. 15 cm
e. 17 cm

12cm.

Explanation:

First we need to calculate the focal length which will be:

= 100 / 4.25

= 23.529

The near point of the machinist will be solved using the equation:

1/u + 1/v = 1/f

where,

v = -25

f = 23.529

1/u + 1/v = 1/f

1/u - 1/25 = 1/23.529

1/u = 1/23.529 + 1/25

u = 12.12cm

u = 12cm approximately

Therefore, the near point of the machinist is 12cm

f=ma newton

f=100x2.5=250n