How long does it take a 750 W heater operating at full rating to raise the temperature of 1 kg of water from 40oC to 70oC? (Take the specific heat capacity ...

Answer Details

To solve this problem, we can use the formula: Q = mcΔT Where Q is the heat energy required, m is the mass of water, c is the specific heat capacity of water, and ΔT is the change in temperature. We can calculate Q as follows: Q = (1 kg) x (4200 J/kg K) x (70°C - 40°C) Q = 126,000 J We can then use the formula: P = Q/t Where P is the power of the heater in watts and t is the time taken to heat the water. Rearranging this formula to solve for t, we get: t = Q/P Substituting the values we know, we get: t = (126,000 J) / (750 W) t = 168 seconds Therefore, it will take the 750 W heater operating at full rating 168 seconds to raise the temperature of 1 kg of water from 40°C to 70°C. The answer is (c) 168s.