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Two identical thin plano-convex glass le...

Two identical thin plano-convex glass lenses (refractive index 1.5) each having radius of 20 cm are placed with their convex surfaces in contact at the centre. The intervening space is filled with oil of refractive index 1.7. The facal length of the combination is

A

`- 20 cm`

B

`-25 cm`

C

`-50 cm`

D

50 cm

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TARGET PUBLICATION-OPTICS-EXERCISE
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  5. A plano-convex lens fits exactly into plano-concave lens as shown in t...

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  6. A comvex lens and a concave lens are placed in contact. The ratio of m...

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  9. A bi-convex lens is formed with two thin plano convex lenses as shown ...

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  13. The graph between angle of deviation (delta) and angle of incidence (i...

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  14. Two beams of red and violet colours are made to pass separately throug...

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  15. A ray is incident at an angle of incidence i on one surface of a small...

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  16. A ray of light is incident at an angle of 60^(@) on the face of a pris...

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  17. In an experiment for determination of refractive index of glass of a p...

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  18. The angle of incidence for a ray of light at a refracting surface of a...

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  19. Angle of minimum deviation for a prism of refactive index 1.5, is equa...

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