Table of Contents
Which is more important group velocity or phase velocity?
Phase velocity: In a normal medium, the phase velocity is greater than the group velocity.
Why is group velocity more important?
From the dynamics view, group velocity has a physical significance– the rate of energy transport, which makes it more important than the phase velocity. We can see that the carrying waves move from behind and vanish in the front of a wave packet since the phase velocity is greater than the group velocity.
How does group velocity differ from phase velocity?
Phase velocity is defined for both, the single waves and superimposed waves. The group velocity is defined only to the superimposed waves. The group velocity is the velocity of the wave with lower frequency, but the phase velocity is the velocity of the wave with higher frequency.
Why should a matter wave move with group velocity and not phase velocity?
The phase velocity actually don’t carry any meaningful physical information for matter wave. All the meaningful information (like, momentum, velocity etc) contains in the group wave. So the velocity of the particle is determined by the group velocity, not phase velocity.
Which of the following is the correct relation between the group velocity and the phase velocity in a dispersive medium?
Which of the following is the correct relation between the group velocity and the phase velocity? Explanation: The relation between the phase velocity and the group velocity is given by: vg = vp – λdvp/dλ.
Why velocity of matter waves is greater than velocity of light?
Matter waves can propagate in a vacuum. Hence they are not mechanical wave. The number of de-Broglie waves associated with the nth orbital is n. The phase velocity of matter waves can be greater than the speed of light.
Why do matter waves move with group velocity?
As momentum of every particle is different because momentum p= mv which means that the mass and the velocity of particle is different for different particle. Means as wavelength changes the velocity also changes. Because mass and Planck constant remains constant for the particular particle of the matter.
What is the relationship between phase velocity and group velocity?
In a wave packet, the carrier wave travels with the phase velocity. But, when we deal with a particle or wave packet, the phase velocity isn’t important. The relationship between the phase velocity and the group velocity depends on the material properties of the medium.
What is the phase velocity of a wave packet?
The velocity of component waves of a wave packet is known as the phase velocity of those waves. This is the expression for the phase velocity. The velocity of wave packet or the wave packet obtained due to superposition of waves traveling in a group is known as the group velocity.
What is the phase velocity of non-dispersive medium?
In non- dispersive mediums, the phase velocity of waves does not depend on the wavelength. So, the phase velocity equals to the group velocity. For example, the phase velocity is equal to the group velocity when sound waves travel through the air as air is a non- dispersive medium for sound waves.
What is the group velocity in quantum physics?
In quantum physics, the idea of group velocity comes with the idea of wave packets or pulses. A wave packet can be obtained by adding up many waves having different wave numbers and amplitudes. So, the position of a particle can be localized within a specific region by using such a wave packet which represents a particle.