m = mass held by mr. Z above his head = 200 kg
g = acceleration due to gravity = 9.8 m/s²
F = force applied by mr. Z to hold the mass
Using equilibrium of force , force equation is given as
F = mg
F = (200) (9.8)
F = 1960 N
Since the mass is not moved,
d = displacement of the mass = 0 m
we know that , work done is given as
W = F d
inserting the values
W = (1960) (0)
W = 0 J
Answer
given,
diameter of sphere = 5 cm
radius of sphere = -2.5 cm
refractive index for glass n₁ = 1.5
refractive index for air n₂ = 1
magnification of the glass = ?
now,



S' = - 10 cm
magnification


m = + 3