Kisi Difraksi

\(N = 3000 \text{ garis/cm}\)

\(d = \dfrac{1}{3000} \text{ cm}\)

\(d \cdot \sin \theta = n \cdot \lambda\)

\(\dfrac{1}{3000} \cdot \sin 8^{\circ} = 1 \cdot \lambda\)

\(\dfrac{1}{3000} \cdot 0,14 = 1 \cdot \lambda\)

\(\lambda = 4,67 \times 10^{-5} \text{ cm}\)

\(\lambda = 4,67 \times 10^{-7} \text{ m}\)

\(\lambda = 600 \times 10^{-9} \text{ m} = 600 \times 10^{-6} \text{ mm}\)

\(N = 200 \text{ garis/mm}\)

\(d = \dfrac{1}{N} = \dfrac{1}{200} \text{ mm}\)

(A)  Menentukan sudut deviasi orde kedua

\(d \sin \theta = n \cdot \lambda\)

\(\dfrac{1}{200} \cdot \sin \theta = 2 \times 6 \times 10^{-6}\)

\(\sin \theta = 0,24\)

\(\theta = 13,89^{\circ}\)

(B)  Menentukan orde maksimum yang mungkin terlihat di layar

Orde maksimum terjadi saat \(\sin \theta = 1\)

\(d \cdot \sin \theta = n \cdot \lambda\)

\(\dfrac{1}{200}\cdot 1 = n \cdot 600 \times 10^{-6}\)

\(n = 8,33 \approx 8\)

Kondisi awal

\(d \cdot \dfrac{y}{L} = n \cdot \lambda\)

\(\dfrac{1}{1000} \text{ cm } \cdot \dfrac{12 \text{ cm}}{120 \text{ cm}} = 3 \cdot \lambda\)

\(\lambda = \dfrac{1}{30.000}\text{ cm}\)

Kondisi akhir

\(d \cdot \dfrac{y}{L} = n \cdot \lambda\)

\(\dfrac{1}{1000} \text{ cm } \cdot \dfrac{y \text{ cm}}{100 \text{ cm}} = 3 \cdot \dfrac{1}{30.000}\text{ cm}\)

\(\dfrac{1}{100.000} \cdot y = \dfrac{1}{10.000}\)

\(y = 10 \text{ cm}\)