Physics Ex-47

Eye

Mirror

Given a plane mirror, a point

object (P) and the position of an observer’s eye, determine whether or not the observer can see object point P.

P

P'

To determine whether or not the observer can see the given object,

we first locate the image of the object.

Next, we draw a line from the image point to the observer (eye).

If the line intersects the mirror, the observer can see the image.

If the line does not intersect the mirror, then the observer cannot

see the image.

Object point

To find the location of the image point, we start by drawing a line

perpendicular to the mirror and extend it beyond the mirror.

Perpendicular to mirror

Next, since the image distance equals the object distance,

we mark off the image point, P‘, along the extended line.

Object

distance

Image

distance

Image point

Finally, we draw a straight line from the

observer’s eye to the image point.

If this line intersects the mirror,

the observer can see the image.

If this line does not intersect the mirror,

the observer cannot see the image.

Look! The line does not intersect the mirror.

Conclusion: observer cannot see the image.

ANSWER

The observer cannot see the image.

Click

Object distance = Image distance