When observed from the earth,the angular diameter of the solar disc is 32 minutes of arc .Determne the diameter of the image of the sun formed by a convex lens of focal length 25 cm.

A telescope has objective lens of focal length 15m. If this telescope is used to view the moon, what is the diameter of the image of the moon formed by the objective lens? The diameter of the moon is 3.48 xx 10^6m , and the radius of lunar orbit is 3.8 xx 10^8m .

A beam of light converges at a point P. Now a lens is placed in the path of the convergent beam 12cm from P. At what point does the beam converge if the lens is: a convex lens of focal length 20cm?

A thin douel convex lens has surfaces of radii of curature 30 cm each.Find the refractive index of the material of lens,if the focal length is 25 cm.

Calculate the position of image, when an object is placed at a distance of 15 cm from a convex mirror having focal length 0.45 m.

Show that a convex lens produces an N times magnified image,when the object distances from the lens have magnitude (f+- f//N) .Here,f is the magnitude of the focal length of the lens.Hene,find the two values of object distance,for which a convex lens of power 2.5 D will produce an image that is four times as large as the object.

An astronomical telescope has an objective lens of focal length 20 m and eyepiece of focal lengh 1 cm. If this telescope is used to view the moon, find the diameter of the image formed by the objective lens given the diameter of the moon is 3.5 xx 10^6 m and radius of lunar orbit is 3.8 xx 10^8 m .

An object is at a distance of 5 m from a convex mirror of focal length 10 cm.Where is he image formed ?

Draw a ray diagram to show how the image is formed when the object is placed between f and 2 f distances from a convex lens.Deduce the relation between the distances of he oject and the image from the lens and the focal length of the lens under this condition.

A double convex lens has 10 cm and 15 cm as its two radii of curvature.The image of an object,placed 30 cm from the lens,is formed at 20 cm from the lens on the other side.Find the refractive index of the material of the lens.Whgat will be the focal length ?What will be the focal length of the lens,if it is immersed in water of refractive index 1.33?