Define the term wave motion?

Write the characteristics of wave motion.

Two friends A and B are standing a distance x apartin an open field and wind is blowing from A to B.A beats a drum and B hears the sound t_1 timed after he sees the event. A and B intechange their positions and te experiment is repeated. This time B hears teh drum t_2 time after he sees the event. Calculte teh velocity of sound in still air v and the velocity of wind u. Neglect the tiem light takes in travelling between the friends.

Two friends A and B are standing a distance x apart in an open field and wind is blowing from A to B. A beats a drum and B hears the sound t_1 timed after he sees the event. A and B interchange their positions and the experiment is repeated. The velocity of sound in still air is v and the velocity of wind is u . This time B hears the drum t_2 time after he sees the event. Suppose A and B change their positions in such a way that the line joining them becomes perpendicular to the direction of wind while maintaining the separation x . What will be the time lag B finds between seeing and hearing the drum beating by A?

What are the reasons to believe that light is a wave motion?

You are walking along a street. If you just choose a stranger crossing you, what is the probability that his next birthday will fall on a sunday?

You are walking along a street. If you just choose a stranger crossing you, what is the porbability that his next birthday will fall on a Sunday ?

A train standing in a station-yard, blows a whistle of frequency 400Hz in still air. The wind starts blowing in the direction from the yard to the station with a speed of 10 ms^(-1) . What are the frequency wavelength and speed of sound for an observer standing on the station.s platform? Is the situation exactly identical the case when the air is still and the observer runs towards the yard at a speed of 10 ms^(-1) ? The speed of sound in still air can be taken as 340 ms^(-1)

How will you measure the work done ? When the force is inclined to the direction of motion of the body ?

In both p and n type semiconductors , actually electrons are flowing . What difference do you observe in the motion of electron in these two semiconductors ?