Question

Two students X and Y are using one lens each to observe the letters on a piece of paper. Student X

observes bigger and erect letters one a piece of paper. Student X observes bigger and erect letters whereas to

student Y, the letters appear smaller and erect, through the lens.

On the basis of above information answer the following questions.:----


(a) Which type of lenses are being used by student X and Y each.

(b) Draw a ray diagram to show the image formed by the lens used by student Y.

(c) Write two uses of the lens used by student X.​

Answer 1

$\Large{ \underline{\underline{ \purple{ \bf{Information \:provided::}}}}}$

• Student X observes bigger and erect letters by the lens used.
• Student Y, the letters appear smaller and erect by the lens used.

$\Large{ \underline{\underline{ \purple{ \bf{Required \: answer:}}}}}$

a) Lens used by Student X produces images of bigger size and erect which means the image is virtual. Virtual and magnified images are produced by Convex lens.

Lens used by Student Y produces images of smaller size and erect which means the image is virtual. Virtual and diminished image is formed by Concave lens.

b) The Image formed by the Concave lens used by Student Y is in the attachment. There are two cases possible. Object is placed at infinity or between infinity and optical centre.

c) Student X used Convex lens which are used widely due to the image formation with respect to distance of object from the mirror:

• Used in microscopes and camera lens.
• Used in Magnifying lens.
• Used in flashlights.
• Used in glasses for far-sightedness.

Answer 2

$\huge{\underline{\underline{\boxed{\sf{\purple{Answer ࿐}}}}}}$

• a) Lens used by Student X produces images of bigger size and erect which means the image is virtual. Virtual and magnified images are produced by Convex lens.

• Lens used by Student Y produces images of smaller size and erect which means the image is virtual. Virtual and diminished image is formed by Concave lens.

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• b) The Image formed by the Concave lens used by Student Y is in the attachment. There are two cases possible. Object is placed at infinity or between infinity and optical centre.

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• c) Student X used Convex lens which are used widely due to the image formation with respect to distance of object from the mirror:

1. Used in microscopes and camera lens.
2. Used in Magnifying lens.
3. Used in flashlights.
4. Used in glasses for far-sightedness.

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