- + D Page view F it to page ZCT103 SULIT (b). The figure 2 below shows a transparent plastic block with a thin wedge of
Posted: Sun Jul 17, 2022 7:48 pm
- + D Page view F it to page ZCT103 SULIT (b). The figure 2 below shows a transparent plastic block with a thin wedge of air. Red light with wavelength 1 = 632 nm is directed downward through the top of the block. Some of the light that passes into the plastic is reflected back up from the top and bottom surfaces of the wedge, which acts as thin film of air with thickness that varies from L to LR. An observer looking down on the block sees an interference pattern consisting 6 dark fringes and 5 bright red fringes along the wedge. What is the change in thickness AL = L - Lp) along the wedge? Refractive index of air is 1.0. [Rajah 2 di bawah menunjukkan blok plastik lutsinar dengan baji udara nipis. Cahaya merah berjarak gelombang 1 =632 nm ditujukan ke bawah melalui permukaan blok. Sebahagian cahaya yang menembus plastik terpantul ke atas dari permukaan-permukaan atas dan bawah baji yang bertindak sebagai filem udara nipis dengan ketebalan yang berubah-ubah dari Ll to LR Seorang pemerhati melihat ke bawah ke arah blok dan melihar corak interferens mengandungi 6 jalur gelap dan 5 jalur merah cerah sepanjang baji. Berapakah perubahan ketebalan AL (= L - LR sepanjang baji? Indeks biasan bagi udara ialah 1.01 (40/100) Incident light 5 bright red fringes