Question

an immersion heat can supply heat at a rate of 5.2 x 10 to the power of 2 joules per second. calculate the time that it wil take to completly evaporate 1.25 x 10 to the power of minus 1 kg water initially at a temperature of 21 degrees celsius

Answer 1

Power*time= Heat= Mass*Hvwater + Mass*(100-21)*specific heat of water.

Watch specific heat, heat of vaporization units, make certain they match your mass units.
Solve for time.