Prove that the group velocity of acoustic wave at Brillouin
boundary is zero (or a standing wave), also prove that the group
velocity of optical branch at point is also
zero.
Prove that the group velocity of acoustic wave at Brillouin boundary is zero (or a standing...
1. (a) Estimate the size of the phonon energy gap in NaCl relative to the energy of an acoustic phonon at the Brillouin zone, using the diatomic linear chain model. (b) Using the dispersion relation for the diatomic linear chain model, demonstrate that the group velocity vanishes on approach to the Brillouin zone edge for both the acoustic and optical branches. Please show each step with explanation, if possible. Thank you in advance.
How can the standing wave have a velocity? A. It is the superposition of two traveling waves that have velocities. B. The standing wave is moving itself at a certain velocity. C. a standing wave can't have a velocity because it is standing D. a standing wave only consists of one traveling wave that is moving at a velocity
Consider a semi-infinite canal with initial depth of 5 m and initial velocity of zero. A pumping station at the (left) boundary of the canal starts withdrawing water as a result of which an expansion wave starts traveling along the canal. Consider a point on the expansion wave in which the velocity is -0.5 m/s. (a) Calculate the water depth at this point. (b) Determine the speed with which this point propagate along the canal. 1.
Hydraulics please answer A and B please if u can’t leave it
for someone could please.
Consider a semi-infinite canal with initial depth of 5 m and initial velocity of zero. A pumping station at the (left) boundary of the canal starts withdrawing water as a result of which an expansion wave starts traveling along the canal. Consider a point on the expansion wave in which the velocity is-0.5 m/s. (a) Calculate the water depth at this point. (b) Detemine...
Please answer WARM-UP Questions #1-6.
PROBLEM #2: STANDING WAVE PATTERNS While talking to a friend on the phone you play with the telephone cord. As you shake the cord, you notice the ends of the cord are stationary whi vibrates back and forth; you have a standing wave. As you change the motion of your hand, a new pattern develops in which the middle of the cord is stationary while the rest of the cord vibrates wildly. You decide to...
What is the correction value if a standing wave with a velocity of 40 000 cm/s is formed by a tuning fork which has a frequency of 380 Hz in a tube with a length of 20? 19.962 cm 0 0.038 cm 6.32 cm 26.32 cm
Consider the 4th harmonic (standing wave with n = 4) on a string of length L with fixed ends, mass density μ and tension T .a) On a standing wave, the nodes are the points that are not moving, and the antinodes the ones that move with the biggest amplitude. How many nodes and antinodes are on the 4th harmonic? Count them and make a graph of the function clearly showing where all the nodes and antinodes are located. b)...
12. A longitudinal standing wave can be created in a long, thin aluminum rod by stroking the rod with very dry fingers. This is often done as a physics demonstration, creating a high-pitched, very annoying whine. From a wave perspective, the standing wave is equivalent to a sound standing wave in an open-open tube. In particular, both ends of the rod are anti-nodes. What is the fundamental frequency of a 2.50 m -long aluminum rod? The speed of sound in...
QUESTIONS 1. Calculate the velocity of the wave when the string is vibrating in three segments. 2. Suppose the pulley absorbs a significant fraction of the energy in the wave so that the ampli- tude of the reflected wave is not equal to the amplitude of the wave set up by the vibrator How will the standing waves differ from those established under conditions of perfect reflec- tion? Hint: Remember what happens to the nodes when you add two waves...
A standing wave results from the sum of two transverse traveling waves given by y1 = ymcos(kx - ωt) and y2 = ymcos(kx + ωt) where ym = 0.047 m, k = 3.2 rad/m, and ω = 12 rad/s. (a) What is the smallest positive value of x that corresponds to a node? Beginning at t = 0, what is the value of the (b) first, (c) second, and (d) third time the particle at x = 0 has zero...