Advertisements
Advertisements
प्रश्न
Find the radius of curvature of the convex surface of a plano-convex lens, whose focal length is 0.3 m and the refractive index of the material of the lens is 1.5.
Advertisements
उत्तर
The focal length of a combined lens can be determined by the formula
`1/f =(mu -1)(1/R_1 - 1/R_2)`
Here, R_2 =∞ and f =0.3m
`1/0.3 =( mu-1) xx 1/R_1`
`R_1 = 0.3(mu-1)`
`=0.3(1.5 -1)`
` =0.3 xx 0.5`
`= 0.15m`
`=15 cm`
APPEARS IN
संबंधित प्रश्न
Give the usual name for the following:
A point inside a lens through which the light passes undeviated.
Which one of the following materials cannot be used to make a lens?
Which has more power : a thick convex lens or a thin convex lens, made of the same glass? Give reason for your choice.
What is the nature of a lens having a power of + 0.5 D?
A thin converging lens is formed with one surface convex and the other plane. Does the position of image depend on whether the convex surface or the plane surface faces the object?
A double convex lens has two surfaces of equal radii R and refractive index \[m = 1 \cdot 5\]
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?
If the lens is of focal length 25 cm. Calculate the power of the lens.
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.
