In a flask, 114.0 g of water is heated using $67.0 \mathrm {~W}$ of power, with perfect efficiency. How long will it take to raise the temperature of the water from $15 ^ { \circ } \mathrm { C }$ to $25 ^ { \circ } \mathrm { C } ?$ The specific heat of water is 4186 J/kg ? K.
A)71 s
B)4.1 s
C)17 s
D)320,000 s

Question

Quizplus · Accepted Answer

The energy required to heat the water is calculated using the formula $ Q = mc\Delta T $. Here, $ m = 0.114 \, \text{kg} $, $ c = 4186 \, \text{J/kg} \cdot \text{K} $, and $ \Delta T = 10 \, \text{K} $. So, $ Q = 0.114 \times 4186 \times 10 = 4772.4 \, \text{J} $. The time $ t $ is given by $ t = \frac{Q}{P} = \frac{4772.4}{67} \approx 71 \, \text{s} $.

In a Flask, 114 67.0 W67.0 \mathrm {~W}67.0 W Of Power, with Perfect Efficiency

In a Flask, 114 $67.0 \mathrm {~W}$ Of Power, with Perfect Efficiency