Superposition Of Waves

Question 1

How are stationary waves formed ?

Answer 1

Stationary waves are formed by the superposition of two identical waves travelling in opposite direction.

Question 2

What do you mean by ‘identical wave’ ?

Answer 2

By identical wave we mean that the waves must have the same value of v, ω and k.

Question 3

What are antinodes?

Answer 3

Antinodes are points where amplitude of waves is maximum. ( or A1+ A2 ). Antinodes are also called points of constructive interference.

Question 4

Why are nodes ?

Answer 4

Nodes are point where amplitude is minimum ( or A1-A2). Nodes are also called points of destructive interference.

Question 5

What happens when amplitudes A1 and A2 are same or equal? ( to say A) ?

Answer 5

Then the amplitude at antinodes is 2A and at nose is zero. In this case points at node do not oscillate.

Question 6

Which points ( Node or antinodes ) have minimum and maximum energy of oscillation ?

Answer 6

Points at antinodes have maximum energy of oscillations and points at nodes have minimum( Zero when A1=A2)

Question 7

When are points in wave motion said to be in the same phase and when are they said to be out of phase ?

Answer 7

Points lying between two successive nodes are in same phase and points lying between two neighbouring successive nodes are said to be out of phase.

Question 8

Why is the general eq of a stationary wave ?

Answer 8

y= 2A sin kx cos ωt.

Question 9

What is the formula of frequency of a oscillations of a stretched wire or organ wire ?

Answer 9

f= n(v/2l). Using this even and odd both harmonica are obtained. 
v= √T/μ=√T/pS