Which of the following represents an upright image? a. -do b. +m c. -m d. +do

B. +m

Explanation:

The magnification of an image is defined as the ratio between the size of the image and of the object:

where we have

y' = size of the image

y = size of the object

There are two possible situations:

- When m is positive, y' has same sign as y: this means that the image image is upright

- When m is negative, y' has opposite sign to y: this means that the image is upside down

Therefore, the correct option representing an upright image is

B. +m

the part of the wave he is travelling on is the crest