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प्रश्न
The lens of power + 1·0 D is ______.
विकल्प
Convex of focal length 1·0 cm
Convex of focal length 1·0 m
Concave of focal length 1·0 cm
Concave of focal length 1·0 m.
उत्तर
The lens of power + 1·0 D is convex of focal length 1·0 m.
संबंधित प्रश्न
Which one of the following materials cannot be used to make a lens?
Fill in the following blank with suitable word:
For converging lenses, the power is __________ while for diverging lenses, the power is ___________.
An object of height 4 cm is placed at a distance of 15 cm in front of a concave lens of power, −10 dioptres. Find the size of the image.
The power of a lens is +2.0D. Its focal length should be :
How is the power of a lens related to its focal length?
A normal eye is not able to see objects closer than 25 cm because
Which lens has more power a thick lens or a thin lens?
If focal length of a convex lens is 20 cm at what is the power of the lens?
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 focal length of a double convex lens is equal to the radius of curvature of either surface. What is the refractive index of its material?
