Question

1.Определите количество теплоты, выделяемое стальной спиралью длиной 50 см и поперечным сечением 0,5 мм за 15 минут при силе тока 2А. Решение нужно. Там дано|решение

Answer 1

T=15мин=900с
L=50см=0.5м
S=0.5мм=0.0005м
I=2А
q(ро)=0.1
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Q-?

Q=*R*t
Найдем R
R=q*=0.1*=100Ом
Q=*100*900=360000Дж

Answer 2

Calculating Heat Generated by the Steel Coil

To calculate the amount of heat generated by the steel coil, we can use the formula:

Q = I^2 * R * t

Where: - Q = heat generated (in joules) - I = current (in amperes) - R = resistance (in ohms) - t = time (in seconds)

First, we need to calculate the resistance of the steel coil using the given dimensions and then use it to find the heat generated.

Calculating Resistance (R)

The resistance of the steel coil can be calculated using the formula:

R = ρ * (L / A)

Where: - R = resistance (in ohms) - ρ = resistivity of the material - L = length of the steel coil - A = cross-sectional area of the steel coil

Given: - Length (L) = 50 cm = 0.5 m - Cross-sectional area (A) = 0.5 mm^2 = 0.5 * 10^-6 m^2 - Current (I) = 2 A - Time (t) = 15 minutes = 900 seconds

Calculating Resistivity (ρ)

The resistivity of steel is approximately 6.9 x 10^-7 ohm-meter.

R = (6.9 x 10^-7) * (0.5 / (0.5 * 10^-6)) R = 6.9 ohms

Calculating Heat Generated (Q)

Now, we can calculate the heat generated using the formula:

Q = I^2 * R * t Q = (2^2) * 6.9 * 900 Q = 24.6 kJ

Therefore, the amount of heat generated by the steel coil is approximately 24.6 kJ over the 15-minute period with a current of 2A.

This calculation is based on the provided dimensions and standard resistivity values for steel.