Question

A watch shows time as 3:25 when see through a mirror, time appeared will be then:
A. 8:35
B. 9:35
C. 7:35
D. 8:25

Answer 1

Hint: The image formed in plane mirror shows lateral inversion. The left side of the object appears to be the right side of the image and the right side of the object appears to be left side of the image. This property of the inversion of the side is called lateral inversion.

Complete step by step solution:
Due to lateral inversion during formation of the image in the plane mirror the actual time in the watch is different from the time shown in the watch. If we see the watch in the mirror then the time shown is anti-clockwise.
1’O in the watch appears to be 11’O clock in the image formed in the mirror.
2’O in the watch appears to be 10’O clock in the image formed in the mirror.
3’O in the watch appears to be 9’O clock in the image formed in the mirror.
Using the above analogy, we can form a general formula which relates the actual time shown in the watch with the time shown in the mirror.
Actual time$=11:60-$given time
The given time in shown in the mirror is 3:25
Then the actual time can be calculated as,
Actual time$=11:60-3:25$
$=8:35$

Therefore, the actual time in watch is 8:35 which appears to be 3:25 when seen through the mirror.

The phenomena of the lateral inversion can be visualized using following diagram,

Note: The image formed in the plane mirror is laterally inverted.
The image formed in the plane mirror is of the same size as the object.