question_answer

A wave enters to water from air. In air frequency, wavelength, intensity and velocity are \[{{n}_{1}},\,{{\lambda }_{1}},\,{{I}_{1}}\] and \[{{v}_{1}}\] respectively. In water the corresponding quantities are \[{{n}_{2}},\,{{\lambda }_{2}},\,{{I}_{2}}\] and \[{{v}_{2}}\] respectively; then: [AIPMT 2001]

A)              \[{{I}_{1}}={{I}_{2}}\]

B)                   \[{{n}_{1}}={{n}_{2}}\]

C)  \[{{v}_{1}}={{v}_{2}}\]

D)                   \[{{\lambda }_{1}}={{\lambda }_{2}}\]

Correct Answer: B

Solution :

When a wave enters from one medium to another, its frequency remains unchanged, i.e.,  but wavelength, intensity and velocity get changed.