Estimate the largest distance from which the marking on a metre scale can be seen by a telescope whose objective has a diameter 2.5 cm. The pupil of the eye is 2 mm in diamter.

A hemispherical bowl has inner diameter 11.2 cm. Find the volume of the milk it can hold.

An astronomical refractive telescope has an objective of focal length 20 m and an eyepiece of focal length 2 cm.

A telescope has an objective lens of 10 cm diameter and is situated at a distance of 1 km from two objects.The can be resolved by the telescope, when the mean wavelength of light is 5,000 overset @A ,is of the order of

Find the length of a chord which is at a distance of 24 cm from the centre of a circle whose diameter is 50 cm.

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 .

A paper,with two marks havin separation d,is held normal to the line of sight of an observer at a distance of 50 m.The diamerter of the eye len of he obeserver is 2 mm.the least value of d,so that the marks can be seen as seaarte,will be (The mean wavelength of visible light may be taken as 5000 A )

Find the weight of a lead pipe 3.5 m long. The external diameter of pipe is 2.4 cm and thickness of the pipe is 3 mm and 1 cm. of lead weights 10 g.

A telescope has an objective of diameter of 60 cm. The focal lengths of the objective and eye piece are 2.0 m and 1.0 cm respectively. The telescope is directed to view two distant almost point sources of light (e.g. two stars of a binary). The sources are at roughly the same distance (=10^4 light years) along the line of sight but separated transverse to the line of sight by a distnace of 10^10 m . what will the telescope resolve the two objects i.e. will it see two distinct stars?

An object is plced at a distance of 25 cm from a shperical mierror and its image is formed behind the mirror at a distance of 5 cm.Find the focal length of the mirror.Is the mirror concave or convex in nature?