A sound wave is reflected from a brick wall.
Compared with the incident wave, the reflected wave has-
A. Shorter wavelength
B. A greater amplitude
C. the same speed
D.a greater frequency
E.the same velocity

Question

A sound wave is reflected from a brick wall.
Compared with the incident wave, the reflected wave has-
A. Shorter wavelength 
B. A greater amplitude
C. the same speed
D.a greater frequency
E.the same velocity

fifciol · Answer

assuming that this is a perfect reflection( no loose in energy of wave) the properties of wave (amplitude, wavelength, frequency) must remain the same. So you can now consider what is the difference between the velocity and speed and you should be able to give correct answer

anonymous · Answer

Thank you

fifciol · Answer

is it speed or velocity tha remains the same?

anonymous · Answer

That is not given. What will happen in both cases?

fifciol · Answer

speed is only a scalar while velocity is a vector. the magnitude(speed) doesn't change but velocity changes. Why? Because it changes its direction. Imagine that velocity is an arrow. During reflaction it changes its direction and becomes no longer the same vector, but the length of that arrow(speed) doesn't change so speed is the only quantity that remains constant