Question 19
Quantity of HeatHow long does it take a 750-W heater to raise the temperature of 1 kg of water from 20°C to 50°C. [Specific heat capacity of water = 4200 J kg−1 K−1]
- A.84 s
- B.112 s
- C.168 s
- D.280 s
Show the answer and explanation
Answer: C (168 s)
Explanation
Heat needed = 1 × 4200 × 30 = 126 000 J. t = 126 000/750 = 168 s.