A pile 4m high driven into the bottom of a lake is 1m above the `
`water . Determine the length of the shadow of the pile on the bottom of the lake if `
` the sun rays make an angle of `45^@` with the water surface . The refractive index`
` if water is `4/3`. `

Answer

B

Explanation

From Snell's law,`4/3=sin45^@/sinr `

Solving this equation , we get `r=32^@`
Further, `EF=(DF)tanr=(3)tan 32^@=1.88m`
`:.` Total length of shadow, `L=CF` or `L=(1+1.88)m `
` =2.88m`.