What is the mass of a material, whose specific heat capacity is 400J/(kg°C) for a rise in temperature from 15 °C to 25 °C, when heat received is 20 kJ ?

To find the mass of the material, we use the specific heat formula Q = mcΔT. Given values are: heat received (Q) = 20 kJ = 20,000 J; specific heat capacity (c) = 400 J/(kgC); and temperature rise (ΔT) = 25 C - 15 C = 10 C. Rearranging the formula to solve for mass (m), we get m = Q / (c  ΔT). Substituting the values: m = 20,000 / (400  10). This simplifies to m = 20,000 / 4,000, which equals 5 kg. The calculation ensures consistent units where mass is in kilograms, energy in Joules, and temperature in degrees Celsius. Therefore, the mass of the material is 5 kg, matching option 4.