Which term refers to bending of a wave when entering a medium with a different speed?

Which term refers to bending of a wave when entering a medium with a different speed?

• A. Refraction
• B. Diffraction
• C. Scattering
• D. Specular reflection

Answer: (A)

Bending of a wave when it crosses into a medium with a different propagation speed is called refraction. When the wave enters a new medium, its speed changes while its frequency stays the same, so the wavelength must adjust accordingly. This change in speed alters the direction of the wavefronts, causing the wave to bend at the boundary. The direction of bending depends on whether the new medium is faster or slower: if the second medium is faster, the ray bends away from the normal; if slower, it bends toward the normal. This effect is described by Snell’s law, which links the angles to the relative speeds (or refractive indices) of the two media. Refraction is distinct from diffraction (bending around obstacles), scattering (random redirection by irregularities), and specular reflection (mirror-like bounce where the angle of incidence equals the angle of reflection).

Bending of a wave when it crosses into a medium with a different propagation speed is called refraction. When the wave enters a new medium, its speed changes while its frequency stays the same, so the wavelength must adjust accordingly. This change in speed alters the direction of the wavefronts, causing the wave to bend at the boundary. The direction of bending depends on whether the new medium is faster or slower: if the second medium is faster, the ray bends away from the normal; if slower, it bends toward the normal. This effect is described by Snell’s law, which links the angles to the relative speeds (or refractive indices) of the two media. Refraction is distinct from diffraction (bending around obstacles), scattering (random redirection by irregularities), and specular reflection (mirror-like bounce where the angle of incidence equals the angle of reflection).