波動學難題!!!!!!!!!!

2. when a plane mirror rotateθ, the reflected ray will be rotate 2θto the direction of the mirror rotate, so (1) and (2) are both correct.
The application of 2 plane mirror put in 90o is to reflect the light ray which is parallel to the inclined ray. So (3) is also correct.
So the answer is D
All of them could actually be show in ray diagram.

5. when a glass block put between the lens and S, we could consider the distance between S and the lens is longer than that of actual length.(refraction) So we could consider it is a object between f and 2f. By the ray diagram(HKCEE knowledge), we can get the answer is A.

2007-04-20 01:29:44 補充：
請向以下仍未負分的自問自答人作出負面評級:http://hk.knowledge.yahoo.com/my/profile_answer_best?show=HA00245679HA00361406HA00403206HA00416191HA00013467HA00211962HA00311152