Advertisements
Advertisements
प्रश्न
What does sign of power (+ve or –ve) indicate?
Advertisements
उत्तर
Positive power (+ve) of a lens indicates converging ability of a lens as in the case of convex lens, and negative power (−ve) of a lens indicates its diverging ability as in the case of concave lens.
APPEARS IN
संबंधित प्रश्न
How unit of power related to focal length of a lens?
Find the focal length of a lens of power −2.0 D. What type of lens is this?
Which has more power : a thick convex lens or a thin convex lens, made of the same glass? Give reason for your choice.
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 ___________.
A convex lens of power 5 D and a concave lens of power 7.5 D are placed in contact with each other. What is the :
(a) power of this combination of lenses?
(b) focal length of this combination of lenses?
Define the term focal length of a lens.
Name the type of lens whose power is positive.
The image of an object formed by a lens is real, inverted and of the same size as the object. If the image is at a distance of 40 cm from the lens, what is the nature and power of the lens ? Draw ray diagram to justify your answer.
A double convex lens has two surfaces of equal radii R and refractive index \[m = 1 \cdot 5\]
A pin of length 2.00 cm is placed perpendicular to the principal axis of a converging lens. An inverted image of size 1.00 cm is formed at a distance of 40.0 cm from the pin. Find the focal length of the lens and its distance from the pin.
The power of the magnifying glass depends on the distance of the magnifying glass from object.
