Advertisements
Advertisements
प्रश्न
What is the power of a convex lens lens whose focal length is 80 cm?
Advertisements
उत्तर
Power of a lens is given by:
Power (P) `=1/f`
∴ `p=1/(80xx10^2)=100/80=1.25 D`.
APPEARS IN
संबंधित प्रश्न
Define the power of a lens.
What does sign of power (+ve or –ve) indicate?
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?
What can you see in a completely dark room? If you switch on an electric bulb in this dark room as a light source, explain how you could now see:
(a) the electric bulb
(b) a piece of white paper
Give the usual name for the following:
A point inside a lens through which the light passes undeviated.
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 ___________.
State the condition for the following a ray passes undeviated through the lens .
How does the power of a lens change if its focal length is doubled?
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 convex lens produces a double size real image when an object is placed at a distance of 18 cm from it. Where should the object be placed to produce a triple size real image?
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?
The power of the magnifying glass depends on the distance of the magnifying glass from object.
The power of lens depends on the focal length of the lens
Increase in the converging power of eye lens cause ‘hypermetropia'
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.
The lens of power + 1·0 D is ______.
