PHY1604
ASSIGNMENT 3 2021
QUESTION 1
𝑠𝑝𝑒𝑒𝑑 𝑜𝑓 𝑙𝑖𝑔ℎ𝑡 𝑖𝑛 𝑣𝑎𝑐𝑢𝑢𝑚 𝑐
𝑛= =
𝑠𝑝𝑒𝑒𝑑 𝑜𝑓 𝑙𝑖𝑔ℎ𝑡 𝑖𝑛 𝑚𝑒𝑑𝑢𝑖𝑚 𝑣
𝑐
𝑛=
𝑣
𝑛 = 𝑖𝑛𝑑𝑒𝑥 𝑜𝑓 𝑟𝑒𝑓𝑟𝑎𝑐𝑡𝑖𝑜𝑛 𝑜𝑓 𝑡ℎ𝑒 𝑏𝑙𝑜𝑐𝑘
𝑐
𝑣= ∴ 𝑐 = 3 × 108 𝑚⁄𝑠 ,𝑛 = 3
𝑛
3 × 108
𝑣=
3
𝑣 = 1 × 108 𝑚⁄𝑠
𝑆𝑝𝑒𝑒𝑑 𝑜𝑓 𝑙𝑖𝑔ℎ𝑡 𝑖𝑛𝑠𝑖𝑑𝑒 𝑡ℎ𝑒 𝑏𝑙𝑜𝑐𝑘 = 1 × 108 𝑚⁄𝑠
ANSWER:[3]
QUESTION 2
ANSWER:[5
, QUESTION 3
𝑛1 sin(𝜃1 ) = 𝑛2 sin(𝜃2 )
𝑛1 sin(𝜃1 )
sin(𝜃2 ) =
𝑛2
𝑛1 sin(𝜃1 )
𝜃2 = sin−1 ( )
𝑛2
𝑛1 = 𝑖𝑛𝑑𝑒𝑥 𝑜𝑓 𝑟𝑒𝑓𝑟𝑎𝑐𝑡𝑖𝑜𝑛 𝑜𝑓 𝑎𝑖𝑟 = 1
𝑛2 = 𝑖𝑛𝑑𝑒𝑥 𝑜𝑓 𝑟𝑒𝑓𝑟𝑎𝑐𝑡𝑖𝑜𝑛 𝑜𝑓 𝑡ℎ𝑒 𝑏𝑙𝑜𝑐𝑘 = 1.59
𝜃1 = 𝑎𝑛𝑔𝑙𝑒 𝑜𝑓 𝑖𝑛𝑐𝑖𝑑𝑒𝑛𝑐𝑒 = 50°
𝜃2 = 𝑎𝑛𝑔𝑙𝑒 𝑜𝑓 𝑟𝑒𝑓𝑟𝑎𝑐𝑡𝑖𝑜𝑛
1 sin(50)
𝜃2 = sin−1 ( )
1.59
𝜃2 = 28.8°
𝐷 = 4 sin(28.8°)
𝐷 = 1.93 𝑐𝑚
ANSWER:[3]