關於光學的簡單物理問題

1. Let D be the original distance of object from the mirror. The image will then be at a distance of 2D from the object (Laws of Reflection).

Now, the mirror has moved a distance 0.1 m away from the object, the new distance of the mirror from the object = (D + 0.1) m

The new position of the image will now be at distance of (D+0.1) m behind the mirror. That is, at distance of 2(D+0.1) m from the object.

Therefore, the image has moved a distance of [2(D+0.1) - 2D] m
= 0.2 m

2. Let h be the depth of the liquid.
Since the light rays are incident at critical angle c, given by
sin(c) = 1/1.25
c = 53.13 degrees.
From simple geometry,
tan(c) = radius of circular area/h = (24/2)/h
i.e. h = 12/tan(53.13) cm = 9 cm

1
Answer: 0.1m+0.1m=0.2m Because of love!!!!


2.
Answer:
24-13=9
Because of love

2009-12-29 22:06:52 補充：
sorry , is 24-15=9

1. A fixed object is placed in front of a plane mirror. If the mirror is moved 0.1m away from the fixed object, how far will the image move?



問題：答案為何是0.2m？試詳細解釋。

呢題考你英文，你睇番最尾個句，how far will the image move? 係對應上一句 away from the fixed object，因為 mirror moved 0.1m 所以 image moved 0.2m away from the fixed oject。