Question

Calculate the time necessary for 2 liters of water, initially at 20°C and contained in a cylindrical pot of diameter dP=20cm, to boil on a stove that delivers 10kW/m^2.

Answer 1

time is 35.53 min

Step-by-step explanation:

given data

mass of water m = 2 L = 2kg

temperature = 20°C

diameter dP = 20 cm

rad

delivers = 10 kW/m²

to find out

Calculate the time

solution

we know here energy required to boil water that is

Q = mcΔT .........1

m is mass and ΔT is change in temperature and c is 4186 J/kg°C

so Q = 2 × 4186 × ( 100-20)

Q = 669760 J = 669.760 kJ

so power will be

power =
`{deliver}*{area}`

power =
`{10}{(\pi)/(4) * D^2}`

power =
`{10}{(\pi)/(4) * (0.20*10^(-2))^2}`

power = 0.314159 kW

so

energy = power × time

669.760 = 0.314159 × time

time = 2131.9140 sec

time is 35.53 min