An electric kettle with negligible heat capacity is rated at 2000W. If 2.0kg of water is put in it, how long will it take the temperature of water to rise f...
Question 1 Report
An electric kettle with negligible heat capacity is rated at 2000W. If 2.0kg of water is put in it, how long will it take the temperature of water to rise from 20OC to 100OC? [specific heat capacity of water = 4200Jkg-1k-1]
Answer Details
To solve this problem, we can use the formula:
heat energy = mass * specific heat capacity * temperature change
First, we need to calculate the amount of heat energy required to heat up 2.0kg of water from 20°C to 100°C:
heat energy = 2.0kg * 4200J/kg°C * (100°C - 20°C)
heat energy = 672,000J
Next, we can use the power rating of the kettle to calculate the time required:
power = energy / time
time = energy / power
time = 672,000J / 2000W
time = 336 seconds or 5.6 minutes (to 2 significant figures)
Therefore, the answer is 336 seconds or 5.6 minutes. The correct option is (ii).
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