Question

Сколько теплоты выделится за 40 мин в медном проводнике с поперечным сечением 1,5 мм^2 и длиной 3м, подводящем ток к плитке, если сила тока в спирали 5А?

Answer 1

R=po*l/s  удельное сопр. меди 0,017 ом*мм²/м
R=0,017*3/1,5=0,034 Ом
40 мин=40*60=2400 сек
Q=IU=I²Rt=25*0.034*2400=2040 Дж

Answer 2

Calculation of Heat Generated in a Copper Conductor

To calculate the amount of heat generated in a copper conductor, we need to use the formula:

Q = I^2 * R * t

Where: - Q is the heat generated (in joules) - I is the current flowing through the conductor (in amperes) - R is the resistance of the conductor (in ohms) - t is the time for which the current flows (in seconds)

In this case, the current flowing through the copper conductor is 5A, and the time for which the current flows is 40 minutes. We need to convert the time to seconds before plugging it into the formula.

Conversion of Time to Seconds

To convert 40 minutes to seconds, we multiply it by 60 (since there are 60 seconds in a minute):

40 minutes * 60 seconds/minute = 2400 seconds

Now that we have the time in seconds, we can proceed with the calculation.

Calculation

To calculate the heat generated, we need to determine the resistance of the copper conductor. The resistance can be calculated using the formula:

R = (ρ * L) / A

Where: - R is the resistance (in ohms) - ρ is the resistivity of copper (1.7 x 10^-8 ohm-meters) - L is the length of the conductor (in meters) - A is the cross-sectional area of the conductor (in square meters)

In this case, the length of the conductor is 3m, and the cross-sectional area is 1.5 mm^2. We need to convert the cross-sectional area to square meters before plugging it into the formula.

Conversion of Cross-Sectional Area to Square Meters

To convert 1.5 mm^2 to square meters, we divide it by 1,000,000 (since there are 1,000,000 square millimeters in a square meter):

1.5 mm^2 / 1,000,000 = 0.0000015 m^2

Now that we have the cross-sectional area in square meters, we can proceed with the calculation of resistance.

Calculation of Resistance

Using the formula for resistance, we can calculate the resistance of the copper conductor:

R = (ρ * L) / A = (1.7 x 10^-8 ohm-meters * 3m) / 0.0000015 m^2 = 34 ohms

Now that we have the resistance, we can calculate the heat generated using the formula mentioned earlier:

Q = I^2 * R * t = 5A^2 * 34 ohms * 2400 seconds

Calculating this expression will give us the amount of heat generated in joules.

Please note that the specific heat capacity of copper is not required for this calculation, as we are only calculating the heat generated due to the resistance of the conductor.

Let me calculate the final result for you.