A wooden cube justs floats inside water with a 200gm mass is placed on it. When the mass is removed, the cube floats with its top surface 2 cm above the water level. What is the size of the cube?

a-6cm

b-8cm

c-10cm

d-12cm

anybody who knows plz help

Balancing the forces

mg + σgh                =    ρgh + ρgy   (y is the immersed height of 200gm block)   ..(1)     

Now when block is removed

σgh                        =    ρg(h – 2)

putting the value

2 x 10⁵ – 2 ρg        = ρgy

ρg(y + 2)                = 2 x 10⁵

y                            = 198 cm.

putting this in (1)    

2 x  10⁵ + σ.1000h = 1000h + 198000

According to me here σ (density of wood) should be given to get the Ans.