11.2.1 Reflection, Transmission, and Superposition

Question 1

Reflection, Transmission, and Superposition

Answer 1

• A wave will reflect upon encountering a boundary. In the case of a wave on a rope, the reflected wave has the same shape as the incoming wave, but it is inverted if the rope is not free to move at the boundary.
• Some portion of a wave is also transmitted when a boundary is encountered. The details of the transmitted and reflected waves depend on the media involved.
• When two or more waves overlap in a region of space, the resulting wave is the sum of the individual waves. This is called the principle of superposition.

Question 2

A transverse pulse moves to the right, as shown in the figure. After the pulse encounters a rigid boundary, how does the reflected wave appear?

Answer 2

The pulse is reflected and its shape is inverted as it moves in the opposite direction.

Question 3

Consider two ropes of different densities attached to make one continuous rope. A pulse traveling with velocity v on the lighter section of the rope encounters the denser rope. Which of the following depicts what happens to the pulse at the boundary?

Answer 3

-

Question 4

True or false?
Two pulses identical in form, but inversely shaped, travel toward each other. According to the superposition principle, the two pulses will cancel each other. After interference, both the pulses will disappear.

Answer 4

false

Question 5

Consider two ropes of unequal densities making a continuous rope. Assume there is a constant tension along the full length of the rope. A pulse moves from the denser to the lighter section of the rope. How is the velocity of the pulse affected?

Answer 5

v1 < v2

Question 6

A pulse travels along a dense region of a rope and encounters a lighter region of the rope. Which of the following depicts what happens to the pulse as it crosses the boundary?

Answer 6

-

Question 7

An echo of sound is caused by ________________.

Answer 7

reflected sound waves

Question 8

A pulse moves to the right on a rope whose anchored end is free to move vertically. After encountering the boundary, how is the wave reflected?

Answer 8

-

Question 9

Two identical pulses move toward each other. The maximum displacement of each pulse is 0.25 m. What is the maximum displacement of the combined pulse during interference?

Answer 9

0.5 m

Question 10

Waves combine, or interfere, according to the principle of superposition. Which of the following is incorrect?

Answer 10

Two waves arriving at the same position at different times interfere with each other.