Question

Cahaya melalui kisi 5000 celah/cm menghasilkan spektrum spektrum garis terang orde kedua membentuk sudut 30° terhadap garis normal. Panjang gelombang cahaya tersebut adalah…
a. 3000 Å
b. 4000 Å
c. 5000 Å
d. 6000 Å
e. 8000 Å

Answer 1

N = 5000 celah / cm
d = 1/N = 1/5000
= 0,0002 cm = 2 × 10^-4 cm
= 2 × 10^-6 m

d sin 30° = n × lamda
2 × 10^-6 × 1/2 = 2 lamda
10^-6 = 2 lamda
lamda = 10^-6 / 2
= 0,5 × 10^-6
= 5 × 10^-7 meter × 10^10
= 5× 10^3 Å
= 5.000 Å
Jawaban: C