A point object is located at a distance of 100cm from a screen. A lens of focal length 23 cm mounted on a movable frictionless stad is kept between the source and the screen. The stand is attached to a spring of natureal length 50cm and spring constant `800N//m` as shown in Figure . Mass of the stand with lens is 2 kg. How much impulse P should be imparted to the stand so that a real image of the object is formed on the screen after a fixed time gap? Also find this time gap. (Neglect width width of the stand)

Options

A. `(pi)/(10)sec`
B. `(pi)/(20)sec`
C. `(pi)/(30)sec`
D. `(pi)/(40)sec`

Answer

D