Question

Реостат изготовлен из стальной проволоки (удельное сопротивление стали равно 0,12 Ом·мм²/м) длиной 40 м и площадью поперечного сечения 3,4 мм². Напряжение на зажимах реостата — 43 В. Рассчитай сопротивление реостата. Определи, выдержит ли предохранитель, рассчитанный на 261 А, силу тока в данной цепи. Ответ: сопротивление реостата равно Ом (округли до сотых); поскольку сила тока в цепи равна А (округли до десятых), то предохранитель, рассчитанный на 261 А, такую силу тока (выдержит/не выдержит) (выбери правильный ответ).

Answer 1

Ответ:

1,4 Ом. да. вы́держит

Объяснение:

R=ρl/S=0.12•40/3.4=1.41 Ом

I=U/R=43/1.4=30,4 A

Answer 2

Calculation of Resistance of the Rheostat

To calculate the resistance of the rheostat, we can use the formula:

Resistance (R) = Resistivity (ρ) x Length (L) / Cross-sectional Area (A)

Given the following values: - Resistivity of steel (ρ) = 0.12 Ω·mm²/m - Length of the rheostat (L) = 40 m - Cross-sectional area of the rheostat (A) = 3.4 mm²

Let's substitute these values into the formula:

R = 0.12 Ω·mm²/m x 40 m / 3.4 mm²

To simplify the calculation, we need to convert the units to a consistent system. Let's convert the cross-sectional area from mm² to m²:

A = 3.4 mm² = 3.4 x 10^-6 m²

Now we can calculate the resistance:

R = 0.12 Ω·mm²/m x 40 m / (3.4 x 10^-6 m²)

Calculating this expression gives us the resistance of the rheostat.

Calculation of Current in the Circuit

To determine whether the fuse, calculated to withstand 261 A, can handle the current in the circuit, we need to calculate the current in the circuit.

Given: - Voltage across the rheostat terminals = 43 V

We can use Ohm's Law to calculate the current:

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

Substituting the values:

I = 43 V / R

Now we can calculate the current in the circuit.

Results

After calculating the resistance of the rheostat and the current in the circuit, we have the following results:

- The resistance of the rheostat is 0.141 Ω (rounded to the nearest hundredth). - The current in the circuit is 305.67 A (rounded to the nearest tenth).

Therefore, the fuse, calculated to withstand 261 A, will not be able to handle the current in the circuit.

Please note that the calculations provided are based on the given information and assumptions.