Ice starts forming on the surface of the lake and takes 8 hrs to form a layer of 11 cm thick. How much time will it take to increase the thickness of layer by 2 cm further?

time required to form x thickness of ice is t=ρL2Kθ(x22-x12 )   here ρ is density of ice; L is latent heat of fusion of ice; K is coefficient of thermal conductivity; θ is temperature of atmosphere t α (x22-x12 ) t1=8 hours; x1=0cm;x2=0cm;x3=13cm t2=? t1t2=(x22-x12 )(x32-x22 ) 8t2=112-02132-112 t2=8 x 48121=3.17 hour