Advertisements
Advertisements
प्रश्न
Which of the two has a greater power: a lens of short focal length or a lens of large focal length?
Advertisements
उत्तर
A lens with a shorter focal length will have more power because power varies inversely with focal length .
APPEARS IN
संबंधित प्रश्न
The lens A has a focal length of 25 cm whereas another lens B has a focal length of 60 cm. Giving reason state, which lens has more power: A or B.
What is the power of a convex lens of focal length 0.5 m?
The power of a lens is + 0.2 D. Calculate its focal length.
A doctor has prescribed a corrective lens of power, −1.5 D. Find the focal length of the lens. Is the prescribed lens diverging or converging?
An object of height 4.25 mm is placed at a distance of 10 cm from a convex lens of power +5D. Find (i) the focal length of the lens, and (ii) the size of the image.
The power of a combination of two lenses X and Y is 5 D. If the focal length of lens X be 15 cm :
(a) calculate the focal length of lens Y.
(b) state the nature of lens Y.
What is the unit of power of a lens? Define the unit of power of a lens.
How does the power of a lens change if its focal length is doubled?
Express the power (with sign) of a concave lens of focal length 20 cm.
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.
A 5.0 diopter lens forms a virtual image which is 4 times the object placed perpendicularly on the principal axis of the lens. Find the distance of the object from the lens.
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?
How is accommodation produced?
Which lens has more power a thick lens or a thin lens?
Focal length : metre : : power of lens : _______
According to Rayleigh’s scattering law, the amount of scattering of light is inversely proportional to the fourth power of its ______.
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.
The above lens has a focal length of 10 cm. The object of height 2 mm is placed at a distance of 5 cm from the pole. Find the height of the image.
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.
