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Three light rays start out from a candle flame at the same time. Tothe right of

ID: 1745689 • Letter: T

Question

Three light rays start out from a candle flame at the same time. Tothe right of the candle there is a lens, and to the right of thelens there is a screen. Ray A goes through the edge of the lens.Ray B goes through the center of the lens. Ray C goes through anintermediate part of the lens. All three rays are focused on thescreen. Ray B arrives at the screen first because it travels theshortest path. (Hint: draw the candle, lens, and screen as well asthe three rays.)

If this statement is true, prove it. If false, show why it isfalse.

Explanation / Answer

The statement is false. All the three rays will go to the screen at same time. This is because the ray A travel more distance in the lenswhere as the ray C traveled less distance in lens. As the velocity of the light is less in the lens, thereforeall the rays will come to the screen at the same time.