Question

A bird in air is diving vertically over a tank with speed 6 cm//s Base of the tank is silvered A fish in the tank is rising upward along the same line with speed 4 cm//s[Take:mu_(water)=4//3]

`{:(,"Column-I",,"Column-II"),("(A)","Speed of the image of fish as seen by the bird directly",,"(P)12"),("(B)",underset("from the mirror as seen by the bird")" Speed of the image of fish formed after reflection",,"(Q) 4"),("(C)","Speed of image of bird relative to the fish looking upwards",,"(R) 9"),("(D)",underset("downwards in the mirror")" Speed of image of bird relative to the fish looking",,"(S) 3"):}`

Answer 1

Correct Answer - [(A)R;(B)S;(C)P;(D)Q]
(C) Velocity of bird in water `= 6XX4/3=8 downarrow w.r.t fish = 8+4 =12 downarrow`
(D) Velocity of bird in water after reflection from mirror =`8 uparrow w.r.t fish = 8-4 =4 uparrow`
(A) Velocity of fish in air `= 4xx 3/4 = 3 uparrow`
Velocity of fish w.r.t `= 3+6=9 uparrow`
(B) Velocity of image of fish after reflection from mirror in air `=4xx3/4 = 3 uparrow`
w.r.t bird `=-3+6=3 uparrow`