In general, the quantity of heat energy, Q, required to raise a mass m kg of a substance with a specific heat capacity of c J/(kg °C), from temperature t1 °C to t2 °C is given by:
Q = mc(t2 – t1) joules
So:
(t2-t1) =Q / mc
As we know:
Q = 500 J
m = 0.4 kg
c = 4180 J/Kg °c
We can take t1 to be 0°c
t2 - 0 = 500 / ( 0.4 * 4180 )
t2 - 0 = 0.30°c