F4 physic!(Wave motion)

No. of maxima = 10/2 = 5
There are 5 maxima exist.

2011-11-01 19:45:53 補充：
Thanks for pointing out my mistake. Five (5) maxima is the no. on one side of the central line (including the central maximum). Hence, there are 4 maxima on each side of the central line. The total no. of maxima is thus (4+1 +4) = 9.

2011-11-01 19:47:36 補充：
You may look at the following animation, you could set the source separation and wavelength. Pause the motion and you can count the no. of maxima.

http://www.walter-fendt.de/ph14e/interference.htm

2011-11-01 19:52:10 補充：
The equation invloved is: a.sin(theta) = m.入
i.e. m = a.sin(theta)/入
Setting (theta) = 90 degees (i.e. sin(theta) = 1) includes all maxima on one side of the central line including the central maximum.
This gives m = 10/2 = 5

To 天同:
The answer is 9...