Physics
If a girl puts her pencil into an empty trough and see the pencil from the position as given in the figure below:
(a) What kind of variation will be noticed in the appearance of pencil when water is poured into the trough?
(b) Mention the name of the phenomenon which accounts for the above stated observation.
(c) What is the cause of the observed phenomenon when the pencil is placed in water?
Answer
(a) When a girl puts her pencil into an empty trough, and later pours water in the same trough, the part of the pencil which is immersed in water will look bent or broken.
Below is the diagram showing how the girl's eye sees the pencil through water:
(b) The above observation is based on the phenomenon of refraction of light.
(c) The cause of above phenomenon is refraction of light. Rays starting from the dipped portion of the pencil suffer refraction at the water-air surface. Air is a rarer medium than water. So, the refracted rays bend away from the normal and appear to come from a point slightly above the actual position of the pencil. Hence, the pencil appears bent or broken.
Related Questions
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(i) Name the type of lens which forms the above image.
(ii) Draw a ray diagram to show the formation of the image with the above stated characteristics.
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