Advertisements
Advertisements
प्रश्न
What do you understand by the power of a lens? Name one factor on which the power of a lens depends.
Advertisements
उत्तर
The power of a lens is a measure of the degree of convergence or divergence of light rays falling on it. It is defined as the reciprocal of the focal length of a lens in metres.
i.e., Power = `1/"focal length of lens (in metre)"`
Therefore, the power of a lens depends on the focal length.
APPEARS IN
संबंधित प्रश्न
What does sign of power (+ve or –ve) indicate?
State power of a lens S.I. unit.
How unit of power related to focal length of a lens?
Define 1 dioptre of power of a lens.
Consider two statements A and B given below:
A: real image is always inverted
B: virtual image is always erect
Out of these two statements:
A converging lens has focal length of 50 mm. What is the power of the lens?
A diverging lens has focal length of 3 cm. Calculate the power.
The power of a lens is + 0.2 D. Calculate its focal length.
Fill in the following blank with suitable word:
For converging lenses, the power is __________ while for diverging lenses, the power is ___________.
The power of a lens is + 1.0 D is :
A symmetric double convex lens in cut in two equal parts by a plane perpendicular to the principal axis. If the power of the original lens was 4 D, the power a cut-lens will be
A symmetric double convex lens is cut in two equal parts by a plane containing the principal axis. If the power of the original lens was 4 D, the power of a divided lens will be
A diverging lens of focal length 20 cm and a converging lens of focal length 30 cm are placed 15 cm apart with their principal axes coinciding. Where should an object be placed on the principal axis so that its image is formed at infinity?
Power of a lens is – 4D, then its focal length is
Assertion and reasoning type
- Assertion: Myopia is due to the increase in the converging power of eye lens.
- Reason: Myopia can be corrected with the help of concave lens.
Define power of a lens. What is its unit? One student uses a lens of focal length 50 cm and another of –50 cm. What is the nature of the lens and its power used by each of them?
The same size images are formed by a convex lens when the object is placed at 20 cm or at 10 cm from the lens. The focal length of convex lens is ______ cm.
The lens of power + 1·0 D is ______.
