An electric heating coil rated at 1Kw is used to heat 2kg...
An electric heating coil rated at 1Kw is used to heat 2kg of water for 2 minutes. The initial water temperature is 30oC. Taking the specific heat of the water as 4,000Jkg −1 and neglecting that of the container, the final water temperature is
15.0oC
45.0oC
52.5oC
60.0oC
Correct answer is B
Time = 2mins = 2 × 60 = 120secs
Energy = power × time
1000 × 120 = 120,000J
Energy = mc(θ2 – θ1)
120,000 = 2 × 4000(θ2 – θ1)
θ2 = 30 + 15 = 45 o C