Question

Электроплитка со спиралью из нихрома длиной 1 метр и площадью поперечного сечения 1,5 мм2 нагревает 2 л воды от 20 градусов до 70 градусов сколько времени потребуется если она включена в сеть силовй тока в 5 ампер

Answer 1

A=Q 
Q=cm(t2-t1) 
Q=4200*2*(70-20)=420000 Дж 
R=pl/s 
R=1,1*1/1,5=0,7 Ом
A=I^2*R*t 
t=A/(I^2*R) 
t=420000/(25*0,7)=24000с=6,7ч

Answer 2

Calculation of Heating Time for a 1-Meter Long Electric Stove with a Nichrome Coil

To calculate the time required to heat 2 liters of water from 20 degrees Celsius to 70 degrees Celsius using an electric stove with a 1-meter long nichrome coil and a cross-sectional area of 1.5 mm², we need to consider the power of the stove and the specific heat capacity of water.

1. Power of the Electric Stove: - The power of the stove can be calculated using the formula: P = U * I, where P is the power in watts, U is the voltage in volts, and I is the current in amperes. - In this case, the power of the stove is not provided. However, we are given that the stove is connected to a power supply with a current of 5 amperes. Without the voltage value, we cannot calculate the power accurately.

2. Specific Heat Capacity of Water: - The specific heat capacity of water is the amount of heat energy required to raise the temperature of 1 gram of water by 1 degree Celsius. - The specific heat capacity of water is approximately 4.18 joules per gram per degree Celsius (J/g°C).

3. Calculation of Heat Energy Required: - To calculate the heat energy required to heat 2 liters (2000 grams) of water from 20 degrees Celsius to 70 degrees Celsius, we can use the formula: Q = m * c * ΔT, where Q is the heat energy in joules, m is the mass of water in grams, c is the specific heat capacity of water, and ΔT is the change in temperature. - Substituting the values, we have: Q = 2000 * 4.18 * (70 - 20).

4. Calculation of Heating Time: - The heating time can be calculated using the formula: t = Q / P, where t is the time in seconds, Q is the heat energy in joules, and P is the power in watts. - However, since we don't have the power value, we cannot calculate the heating time accurately.

In conclusion, without the power value of the electric stove, we cannot accurately calculate the heating time required to heat 2 liters of water from 20 degrees Celsius to 70 degrees Celsius using the given electric stove with a 1-meter long nichrome coil and a cross-sectional area of 1.5 mm².