Unit: Geometric Optics
Year: 1996 Question#: 87
Question: Which graph best represents the relationship between image distance (d<sub>i</sub> ) and object distance (d<sub>o</sub>) for a plane mirror?
(1 )
(2 )
(3 )
(4 )
What is this question really asking?
Explanation by: Adriana R and Jenny G
[ Return to question menu ]
Answer 1
INCORRECT
Although the above graph shows the object distance increasing along with the image distance, it is still not right. We expect a direct relation. return to top
Answer 2
incorrect
Since a plane mirror has no focus, the formula: 1/do + 1/di = 1/f
does not apply. When looking in a plane mirror, the farther away the object, the farther away the image is.
return to top
Answer 3
INCORRECT
When reflecting of a plane mirror, the image distance depends on the object distance. The image distance does not remain constant as this graph implies.
return to top
Answer 4
CORRECT
In a plane mirror the object distance and the image distance are always equal. This graph shows that they increase simultaneously at the same rate. return to top
What's this question really asking?
The question is really asking do you understand what a plane mirror is and can you read graphs. return to top
