Assuming that a person of normal sight can read print to such distance that the letters subtend and angle of 5 at his eye, find the height of the letters that he can read at a distance of 12 metres.

At what distance does a man, whose height is 2 metres, subtend an angle of 10’ ?

Assuming that the earth’s radius is 6400 km and that it subtends an angle of 57’ at the centre of the moon, find the distance of the centre of the moon from the earth’s centre.

An athlete runs 4 times around a circular running a path to describe 1760 metres. What is the angle in radians degrees subtended at the centre of the circle, when he had runs a distance of 308 metres?

The angle of elevation of the top of a tower from a point A on the ground is 30^@ . On moving a distance of 20 metres towards the foot of the tower to a point B, the angle of elevation increases to 60^@ . Find the height of the tower and distance of the tower from the point A.

A man is moving away from a tower 41.6 m high at the rate of 2 m/sec. Find the rate at which the angle of elevation of the top of tower is changing, when he is at a distance of 30m from the foot of the tower. Assume that the eye level of the man is 1.6m from the ground.

A tree is broken at a height of 5 m from the ground and its top touches the ground at a distance of 12 m from the base of the tree. Find the original height of the tree.

Consider a 20 W bulb emitting light of wavelength 5000 oversetcircA and shining on a metal surface kept at a distance 2m . Assume that the metal surface work function of 2eV and that each atom on the metal surface can be treated as a cirular disc of radius 1.5 A. will there be photoelectric emission?

Consider a 20 W bulb emitting light of wavelength 5000 oversetcircA and shining on a metal surface kept at a distance 2m . Assume that the metal surface work function of 2eV and that each atom on the metal surface can be treated as a cirular disc of radius 1.5 A. Estimate no. of photons emitted by the bulb per second.[Assume no other losses]