Light always takes the path that requires the shortest distance.

Assertion: Distance is a actual length of the path but displacement is a shortest distance between initial and final position. Reason: Distance is a scalar quantity and it is always positive but displacement is a vector quantity. It may be positive, negative or zero.

To cross the river in shortest distance, a swimmer should swimming an angle theta with the upsteram. What is the ratio of the time taken to swim across in the shortest time to that in swimming across over shortest distance. [Asume that the speed of swimmer in still water is greater than the speed of river flow]

A swimmer can swim in still water with speed v and the river is flowing with speed v//2 . What is the ratio of the time taken to swimming across the river in shortest time to that of swimming across the river over the shortest distance ?

In the figure above, if the edge length of the cube is 4, what is the shortest distance from A to D?

A boatman finds that he can save 6 s in crossing a river by the quickest path than by the shortest path. If the velocity of the boat and the river be, respectively, 17 ms^-1 and 8 ms^-1 , find the river width.

Two particles move with constant velocities towards point O along straight lines in a plane as shown. The shortest distance A and B is

The velocity of a boat in still water is 10 m/s. If water flows in the river with a velocity of 6 m/s what is the difference in times taken to cross the river in the shortest path and the shortest time. The width of the river is 80 m.

The mean free path of a gas molecule is the distance

It takes 5 years for light to reach the earth from a star. Express the distance of star from the earth in (i) light year, (ii) km . Take speed of light = 3xx10^8 m s^(-1) and 1 year = 3.153 xx 10^7 s

In vacum, to travel distance d, light takes time t and in medium to travel distance 5d, it takes time T. The critical angle of the medium is