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प्रश्न
Write the three characteristics of the image formed by a convex lens of focal length 20 cm for the object at distance (i) 10 cm, (ii) 30 cm, (iii) 40 cm, (iv) 60 cm from the lens.
उत्तर
(i) For the object at distance 10 cm, the image is virtual, upright, and enlarged.
(ii) For the object at distance 30 cm, the image is real, inverted, and enlarged.
(iii) For the object at distance 40 cm, the image is real, inverted, and the same size.
(iv) For the object at distance 60 cm, the image is real, inverted, and diminished.
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संबंधित प्रश्न
One-half of a convex lens is covered with a black paper. Will this lens produce a complete image of the object? Verify your answer experimentally. Explain your observations.
Draw a labelled ray diagram to show how a ray of light passes through a parallel sided glass block:
if it hits the glass block at 90° (that is, perpendicular to the glass block)
Fill in the following blank with suitable word:
Parallel rays of light are refracted by a convex lens to a point called the ........
Explain with the help of a diagram, why the convex lens is also called a converging lens.
With the help of a labelled diagram explain how a convex lens converges a beam of parallel light rays. Mark the principal axis, optical centre, principal focus and focal length of the convex lens on the diagram.
State two applications of a convex lens.
If you are to determine to focal length of a convex lens, you should have
(A) a convex lens and a screen
(B) a convex lens and a lens holder
(C) a lens holder, a screen holder and a scale
(D) a convex lens, a screen, holder for them and a scale
Observe the following figure and answer the questions.
a) Which optical instrument shows arrangement of lenses as shown in the figure?
b) Write in brief the working of this optical instrument.
c) How can we get different magnifications in this optical instrument?
d) Draw the figure again and labelled it properly
Draw a ray diagram to illustrate the determination of the focal length of a convex lens using an auxiliary plane mirror.
- In which type of microscope do you find the lens arrangement as shown in the following diagram?
- Write about the working and the use of this microscope.
