A man stands 3m from a plane mirror holding a camera.
(a) To take a photograph of his image, what distance setting of the camera should the man use?
(b) Can he obtain a sharp photograph if he uses an auto-focus camera? Explain briefly.
(Auto-focus camera means emitting an infra-red beam and detecting the beam reflected to calculate the distance)
Reflection of Light (Waves)
2007-04-12 2:36 am
回答 (2)
2007-04-13 11:26 pm
✔ 最佳答案
(a) The distance from the camera to the image is 6m. So, the focus distance of the camera should be set at 6m.(b) No. As the infra-red beam is reflected by the plane mirror, the camera will detect the image distance as 3m.
2007-04-12 2:49 am
A)All distance，because he is stand in front of plant mirror
B)Yes, Infra red and light are EM wave ，they have same properties
B)Yes, Infra red and light are EM wave ，they have same properties
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