Question

Помогите) чему равен ток если 2 литра воды, взятой при. 10 С закипает за 17 минут? кпд чайника 86% . напряжение 220В. определиь сопротивления спирали

Answer 1

c=4200    m=po*V=1000*0.002=2      ΔT=100-10=90 C   U=220  Δt=17*60=1020 c

КПД=0,86

КПД=(с*m*ΔТ)/(I*U*Δt)

I=(c*m*ΔT)/(КПД*U*Δt)=(4200*2*90)/(0.86*220*1020)=.............

R=U/I=...........

Answer 2

Calculation of Power

To determine the power consumed by the kettle, we can use the formula:

Power (P) = Energy (E) / Time (t)

The energy consumed by the kettle can be calculated using the formula:

Energy (E) = Mass (m) * Specific Heat Capacity (c) * Temperature Change (ΔT)

Given that 2 liters of water are taken at 10°C and brought to boiling point (100°C), we can calculate the energy consumed.

Mass (m) = 2 kg (since 1 liter of water is approximately equal to 1 kg) Specific Heat Capacity (c) = 4.186 J/g°C (specific heat capacity of water) Temperature Change (ΔT) = 100°C - 10°C = 90°C

Substituting these values into the energy formula:

Energy (E) = 2 kg * 4.186 J/g°C * 90°C = 753.48 kJ

Now, we know that the kettle reaches boiling point in 17 minutes, which is equivalent to 17 * 60 = 1020 seconds.

Substituting the values of energy and time into the power formula:

Power (P) = 753.48 kJ / 1020 s = 0.738 kW

Efficiency of the Kettle

The efficiency (η) of the kettle is given as 86%. Efficiency is defined as the ratio of useful output energy to the input energy.

Efficiency (η) = Useful Output Energy / Input Energy

In this case, the useful output energy is the energy used to heat the water, which we calculated as 753.48 kJ.

Substituting the values into the efficiency formula:

0.86 = Useful Output Energy / 753.48 kJ

Solving for the useful output energy:

Useful Output Energy = 0.86 * 753.48 kJ = 648.05 kJ

Determining the Resistance of the Heating Element

To determine the resistance of the heating element, we can use Ohm's Law:

Resistance (R) = Voltage (V) / Current (I)

Given that the voltage is 220V, we need to calculate the current.

Power (P) = Voltage (V) * Current (I)

Substituting the values of power and voltage:

0.738 kW = 220V * Current (I)

Solving for the current:

Current (I) = 0.738 kW / 220V = 0.00335 A

Now, we can substitute the values of voltage and current into Ohm's Law to calculate the resistance:

Resistance (R) = 220V / 0.00335 A = 65,672.39 Ω

Therefore, the resistance of the heating element is approximately 65,672.39 ohms.

Please note that the search results provided did not contain relevant information for this specific calculation. The calculations were done based on the given information and general knowledge of physics principles.