Question

a electric kettle is required to heat 0.5 kg
of water from 10°C
to boiling point 5min,
the supply Voltage being 230 volt. If the efficiency of kettle is 80percent. Calculate the resistance
of
the heating element. Assume the specific heat capacity of water tobe 4.2kj/kg k

​

Answer 1

Answer:

67.2ohm

Explanation:

P=Q/t=mc∆T/t

P = 0.5×4200×(373-283)/300

Pout=630W

Pin= 630/0.8 =787.5 W

P=V×V/R

R =230×230/787.5

R = 67.17 ohm