Solution:
According to the question,
Mass of copper m is 100 g = 0.1 kg
Change of temperature is
△t = (70 – 20)0 C = 500 C
Also the specific heat capacity of copper is 390 J kg-1 K-1
Expression for heat required is ==> Q = m × △t × c
Upon substituting values in the expression above, we get the amount of heat required to raise the temperature of 0.1 kg of copper.
Therefore, Q = 0.1 × 50 × 390 = 1950 J