Advertisements
Advertisements
प्रश्न
An object is placed in front of a converging lens. Obtain the conditions under which the magnification produced by the lens is
- negative and
- positive.
उत्तर
- Magnification is negative for the real image formed by a convex lens.
- Magnification is positive for the virtual image formed by a convex lens.
संबंधित प्रश्न
What is meant by a power of a lens? Define its SI unit.
Define 1 dioptre of power of a lens.
The focal length of a convex lens is 25 cm. What is its power?
The power of a lens is + 0.2 D. Calculate its focal length.
Fill in the following blank with suitable words :
The reciprocal of the focal length in metres gives you the _________ of the lens, which is measured in ___________.
Fill in the following blank with suitable word:
For converging lenses, the power is __________ while for diverging lenses, the power is ___________.
Consider three converging lenses L1, L2 and L3 having identical geometrical construction. The index of refraction of L1 and L2 are \[\mu_1 \text{ and } \mu_2\] respectively. The upper half of the lens L3 has a refractive index \[\mu_1\] and the lower half has \[\mu_2\] following figure . A point object O is imaged at O1 by the lens L1 and at O2 by the lens L2placed in same position. If L3 is placed at the same place,
(a) there will be an image at O1
(b) there will be an image at O2.
(c) the only image will form somewhere between O1 and O2
(d) the only image will form away from O2.
Power of a lens is – 4D, then its focal length is
According to Rayleigh’s scattering law, the amount of scattering of light is inversely proportional to the fourth power of its ______.
The power of convex lens of focal length 20 cm is ______.
