What will be the position of the object, when a convex lens of focal length 20 cm, is used to form an erect image which is twice as large as the object?
Correct answer: E. The object is 10 cm from the lens
- A. The object is 2 cm from the lens
- B. The object is 4 cm from the lens
- C. The object is 6 cm from the lens
- D. The object is 8 cm from the lens
- E. The object is 10 cm from the lens
Explanation
The explanation is given below:f=20cm and v=2uSign convention u=+vev=+vef=+ve1/2u-1/u=1/f 1-2/2u=1/20 -1/2u =-1/20 2u=20 u=10cm So the object must be placed 10 cm from the lens.
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Light is studied through reflection, refraction, dispersion, interference, diffraction and polarization, linking ray behavior with its wave nature. Questions may involve mirrors, lenses, optical instruments, refractive index and image formation, while geometrical optics deals with rays and wave optics explains effects such as interference and diffraction.
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