Physics - Heat & Thermo Question with Solution | TestHub

Water at $0^{\circ }\mathrm{C}$ was heated until it started to boil and then until it all changed to steam. The times required are:

time to heat water from $0^{\circ }\mathrm{C}$ to $100^{\circ }\mathrm{C}$ = $5\mathrm{minutes}$

time to change boiling water to steam = $28\mathrm{minutes}$

If the flame supplied heat at a constant rate the specific latent heat of vaporisation of water (neglecting heat losses, container etc.) is, in J/gm. Specific heat of water $c_w=4.2$ J/g.