To warm ships for underwater rocks, a light house throws a red coloured light over a sector of `80o` angle to a distance of 16.5 km. Find the area of the sea over which the ships are warmed.

To warn ships for underwater rocks,a lighthouse spreads a red coloured light over a sector of angle 80^(@) to a distance of 16.5km. Find the area of the sea over which the ships are warned.

Two warn ships for underwater rocks, a lighthouse spreads a redcoloured light over a sector of angle 72^(@) to a distance of 15 km. Find the area of the sea over which the ships are warned. [Use pi=3.14 ]

From the top of a light -house at a height 20 metres above sea -level,the angle of depression of a ship is 30^(@) .The distance of the ship from the foot of the light house is

In Yonung's double-slit experiment, two slits which are separated by 1.2 mm are illuminated with a monochromatic light of wavelength 6000 Å The interference pattern is observed on a screen placed at a distance of 1 m from the slits. Find the number of bright fringes formed over 1 cm width on the screen.

A ring of mass m=1kg can slide over a smooth vertical rod. A light string attached to the ring passing over a smooth fixed pulley at a distance of L=0.7m from the rod as shown in figure. At the other end of the string mass M=5kg is attached, lying over a smooth fixed inclined plane of inclination angle 37^@ . The ring is held in level with the pulley and released. Determine the velocity of ring when the string makes an angle (alpha=37^@) with the horizontal. [sin 37^@=0.6]

The height of a light house is 40 m. The angle of depression of a ship from the top of the light house is 60^(@) . Find the distance of ship from the light house.

Two ships are there in the sea on either side of a light house in such a way that the ships and the light house are in the same straight line. The angles of depression of two ships are observed from the top of the light house are 60o and 45o respectively. If the height of the light house is 200 m, find the distance between the two ships. (U s e sqrt(3)=1. 73)

Two ships are sailing in the sea on the tow sides of a light house . The angles of elevation of the top of the light house as observed from the two ships are 30^(@)and45^(@) respectively . If the light house is 100 m high , the distance be - tween the two ships is :(take sqrt(3)=1.73)

A driver having a definite reaction time is capable of stopping his car over a distance of 30 m on seeing a red traffic signal, when the speed of the car is 72 km/hr andover a distance of 10 m when the speed is 36 km/hr. Find the distance over which he can stop the car if it were running at a speed of 54 km/hr. Assume that his reaction time and the deceleration of the car remains same in all the three cases.

A point source of light B is placed at a distance L in front of the center of a mirror of width d hung vertically on a wall. A man walks in front of the mirror along a line parallel to the mirror at a distance 2L from it, as shown in Fig . Find the greated distance over which he can see the image of the light source form the mirror.