Question

Multiple Choice Questions
1. A student obtain a clear image of window bars on a screen with the help of a convex
in order to have the best image, his teacher suggested him to obtain the image of a dia
Where will the lens has to be moved in order to obtain a clear image?
a. away from the screen
b. behind the screen
c. towards the screen
d. at a very long distance from the screen
2. If you want to make a Refracting Telescope, what components will you choose ?
a. One convex lens and one concave lens.
b. Two convex lenses.
c. One concave mirror, one plane mirror and one convex lens.
d. One concave mirror, one convex mirror and one convex lens.
3. The image obtained while finding the focal length of convex lens is
4. For the same thickness of the lens, if the radius of curvature is increased, the focal length
a. a real and erect. b. virtual and erect. c. real and inverted. d. virtual and invented
d. be imposible to estime
a. reduced
b. remain unchanged.
c. increased.
3. At what distance a watch maker must hold his lens from the watch?
a. at the focal length
b. at less than focal lengh
c. at more than the focal length
d. at zero distance
: Exercise :
1. Explain the working of compound microscope by focal length of convex lens.​

Answer 1

Answer:

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Answer is

Explanation:

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Answer is

Answer 2

Answer:

Your answer is given below:

Explanation:

1. . A student obtain a clear image of window bars on a screen with the help of a convex

in order to have the best image, his teacher suggested him to obtain the image of a distant  

Where will the lens has to be moved in order to obtain a clear image?

a. away from the screen

b. behind the screen

c. towards the screen

d. at a very long distance from the screen

The correct option is c that is towards the screen.

2. If you want to make a Refracting Telescope, what components will you choose ?

a. One convex lens and one concave lens.

b. Two convex lenses.

c. One concave mirror, one plane mirror and one convex lens.

d. One concave mirror, one convex mirror and one convex lens.

The correct option is b that is two convex  lens.

3. The image obtained while finding the focal length of convex lens is

a. a real and erect .

b. virtual and erect.

c. real and inverted.

d. virtual and invented

Ans. The image obtained while finding the focal length of convex lens is real and inverted. This image is obtained by using auxiliary plane mirror.

So the correct option is a that is real and erect.

4.  For the same thickness of the lens, if the radius of curvature is increased, the focal length

a. reduced.

b. remain unchanged.

c. increased.

d. be impossible to estimate.

So the correct option is c that is increased.

5.  At what distance a watch maker must hold his lens from the watch ?

a. at the focal length

b. at less than focal lengh

c. at more than the focal length

d. at zero distance

So the correct option is b that is at less than focal length.

Exercise :

1. Explain the working of compound microscope by focal length of convex lens.

​A compound microscope works on the principle that when a tiny object to be magnified is placed just beyond the focus of its objective lens, a virtual, inverted and highly magnified image of the object is formed at the least distance of distinct vision from the eye held close to the eye piece.

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