# 班級:光電一乙 學號:498L0106 ... 98 學年度第 2 學期物理 Chap24 作業

```班級:光電一乙

98 學年度第 2 學期物理 Chap24 作業
1. A laser beam (λ = 632.8 nm) is incident on two slits 0.200 mm apart. How far
apart are the bright interference fringes on a screen 5.00 m away from the
double slits?
ybright  y m1  y m 
L
(m  1) 
L
m
L
d
d
d
(632.8  10 m)(5.00m)

 1.58  10  2  1.58cm
3
0.200  10 m
9
2. A pair of narrow, parallel slits separated by 0.250 mm is illuminated by the
green component from a mercury vapor lamp (λ = 546.1 nm). The interference
pattern is observed on a screen 1.20 m from the plane of the parallel slits.
Calculate the distance (a) from the central maximum to the first bright region
on either side of the central maximum and (b) between the first and second
dark bands in the interference pattern.
L
(546.1  10 9 m)(1.20m)

 2.62  10 3 m  2.62mm
(a) y 
3
d
0.250  10 m
(b) y  y dark
m 1
 y dark
m 0

L
d
 2.66mm
3. Helium–neon laser light (λ = 632.8 nm) is sent through a 0.300-mm-wide single
slit. What is the width of the central maximum on a screen 1.00 m from the
slit?
ym m

L
W
y1 1  632.8  10 9

 y  2.109  10  2 m
3
1
0.3  10
2 y  4.22  10 3 m
4. A slit of width 0.50 mm is illuminated with light of wavelength 500 nm, and a
screen is placed 120 cm in front of the slit. Find the widths of the first and
second maxima on each side of the central maximum.
1
1
(  m )
(  m)L
y1
 2
 y1  2
L
W
W
1
1
(  m)
(  m)L
y2
 2
 y2  2
L
W
W
1
2
1
2
間隔  y 2 - y1  (  2) - (  1) 
L
W

500  10 -9  1.2
 1.2mm
0.5  10 -3
```