An electric boiler with a 160 Ohm spiral is placed in a vessel containing 0.5 kg of water at 20 ° C.
An electric boiler with a 160 Ohm spiral is placed in a vessel containing 0.5 kg of water at 20 ° C. It was plugged into a network with a voltage of 220 V. After 5 minutes, the spiral was turned off. What is the temperature of the water in the vessel?
1. Let’s find the work performed by an electric boiler according to the formula:
A = U ^ 2: R * t = 220 ^ 2: 160 x 300 = 90750 J
Where:
U – voltage, 220V;
R – resistance, 160 Ohm;
t – time, 5 minutes = 5 * 60 = 300 seconds.
2. From the formula for the amount of heat Q = c × m × (t2-t1), we determine the temperature t2 = Q: c × m + t1
Where:
с – specific heat capacity of water, 4200 J / kgСº;
m is the mass of water, 0.5 kg;
t1 – initial temperature, 20 ° C
t2 = 90750: (4200 × 0.5) + 20 = 63 ° С
Answer: the temperature of the water in the vessel has become 63 ° С
