Question

When a ray of light enters into water from air, then its wavelength :

• A. decreases
• B. increases
• C. remains same
• D. none of these

Answer 1

Answer: (A)

Wavelength $\lambda =\frac{\upsilon }{n}$ When a light ray enters into water from air, the frequency (n) is unchanged but velocity (v) decreases. $\therefore$ $\lambda$ decrease.