Question

1) Which of the following is true when waves have constructive interference at a point in space?

A) The waves are always at their peaks, but they are not always in phase

B) The waves are always at their peaks and they are are always in phase

C) The waves are always in phase, but are not always at their peaks

How do you solve this equation?

To clearly see an image located 25.0 cm from his eye, a far-sighted person wears glasses positioned 1.00 cm from his eye. If his prescription strength is 2.5 diopters, what is his near point?

A) Thin lens equation

B) M = N / f

C) M = -N L / (fefo)

Answer 1

1) C) The waves are always in phase, but are not always at their peaks

The condition for constructive interference is the two waves must be in pahse when they overlap.

2) we are supposed to use A) thin lens equation

from the given data

object distance, u = 25 - 1 = 24 cm

focal length of the lens, f = 1/P

= 1/2.5

= 0.4 m

= 40 cm

let v is the image distance.

now use, 1/u + 1/v = 1/f

1/v = 1/f - 1/u

1/v = 1/40 - 1/24

v = -60 cm

his near point = 60 + 1

= 61 cm <<<<<<<<----------------Answer