One end of a long metallic wire of length (L) is tied to the ceiling. The other end is tied to a massless spring of spring constant . (K.A) mass (m) hangs freely from the free end of the spring. The area of cross- section and the Young's modulus of the wire are (A) and (Y) respectively. If the mass is slightly pulled down and released, it will oscillate with a time period (T) equal to :

Options

A. `2pisqrt((m)/(K))`
B. `2pisqrt((m(YA+KL))/(YAK))`
C. `2pisqrt((mYA)/(KL))`
D. None

Answer

B

Explanation

There is no change of phase in the transmitted ray due to difference in refractive index. In the reflected ray, phase chane occurs when a ray is reflected from an optically denser medium.