The thickness of icein a lakeis 5cmand the atmospherictermperature is -10^(@)C. Calculatethe timerequriedfor the thickness of iceto growto 7cm . Thermalconductivity ofice= 4 xx 10^(-3) cal//cm s-""^(@)C, densityof ice= 0.92g//cm^(3) and latentheat of fusion for ice=80 cal/g.

The thickness of icein a lakeis 5cmand the atmospherictermperature is

1.	The thickness of icein a lakeis 5cmand the atmospherictermperature is -10^(@)C. Calculatethe timerequriedfor the thickness of iceto growto 7cm . Thermalconductivity ofice= 4 xx 10^(-3) cal//cm s-""^(@)C, densityof ice= 0.92g//cm^(3) and latentheat of fusion for ice=80 cal/g.
Answer» Solution :Using `Delta = (RHO L)/(2KT) (x_(2)^(2) - x_(1)^(2))` wehavethe requiredtime `Delta t` as . `Delta t =(92 xx 10^(-2) g//cm^(3))/(2 xx 4xx 10^(-3) "cal/cm"-s-""^(@)C) xx (80 cal//gm)/(10^(@)C) xx (7^(2) - 5^(2))cm^(2)` ` = (92 xx 80 xx 24)/(8) s = 22080 s = 6.13` HR