Unit: optics
Year: 1990 Question#: 95
Question: In the diagram below, a light ray leaves a light source and reflects from a plane mirror. At which point does the image of the source appear to be located?
(1 )A
(2 ) B
(3 ) C
(4 ) D
What is this question really asking?
Explanation by: frances j-p
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Answer 1
A
INCORRECT
A is incorrect because the image is always behind the mirror. return to top
Answer 2
B
CORRECT
Answer B is correct because the image must be the same distance behind the mirror as the source is in front of the mirror. B, C, and D are all the same distance behind the mirror, but B is the point that is in the obsrver's line of sight (from the observer to the point or reflection on the mirror). return to top
Answer 3
C
INCORRECT
C is incorrect because it is not in the observer's line of sight. return to top
Answer 4
D
INCORRECT
D is incorrect because it is not in the observer's liine of sight. In order to see the image here, the source would have to be where the observer is. return to top
What's this question really asking?
Apply the rule for locating images in plane mirrors. return to top
