Water of mass 1.5kg is heated from from 30oC to 80oC using an electric kettle which is rated 5A, 230V. Calculate the time taken to reach the final destinati...
Question 1 Report
Water of mass 1.5kg is heated from from 30oC to 80oC using an electric kettle which is rated 5A, 230V. Calculate the time taken to reach the final destination [specific heat capacity of water 4200Jkg-1K-1]
Answer Details
The amount of heat required to raise the temperature of water can be calculated using the formula: Q = mcΔT Where Q is the heat energy, m is the mass of water, c is the specific heat capacity of water and ΔT is the change in temperature. In this case, the mass of water is 1.5 kg, the specific heat capacity of water is 4200 Jkg^-1K^-1, and ΔT is 80 - 30 = 50 K. So, Q = 1.5 kg x 4200 Jkg^-1K^-1 x 50 K = 315000 J The power rating of the electric kettle is 5A x 230V = 1150W = 1150J/s. Therefore, the time taken to heat the water can be calculated using the formula: t = Q/P where t is the time taken, Q is the heat energy, and P is the power rating of the electric kettle. So, t = 315000 J / 1150 J/s = 273.91 s ≈ 4.57 minutes (to 2 decimal places) Therefore, the time taken to heat the water from 30oC to 80oC using the electric kettle is approximately 4.57 minutes. Hence, the correct option is (a) 4.57 minutes.
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