Question

Электрическую лампу сопротивлением 240 Ом , рассчитанную на напряжение 120 В надо питать от сети напряжением 220В ...   Какой длины нихромовый проводник площадью сечения 0,55 мм в квадрате надо включить последовательно с лампой? P = 110* 10 в минус 8 степени Ом * м. Ничего не смыслю в физике! Помогите, пожалуйста, и поподробнее (для тупых) :D )) заранее спасибо)!

Answer 1

Calculation of the Length of the Nichrome Wire

To determine the length of the nichrome wire required to be connected in series with the lamp, we need to consider the resistance of the lamp and the desired voltage.

Given: - Resistance of the lamp: 240 Ω - Desired voltage: 220 V

To calculate the length of the nichrome wire, we can use the formula for the resistance of a wire:

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

Where: - Resistivity (ρ) is a property of the material (in this case, nichrome) - Length (L) is the length of the wire - Cross-sectional Area (A) is the area of the wire's cross-section

We can rearrange the formula to solve for the length (L):

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

To find the cross-sectional area of the wire, we are given the area in square millimeters (mm²). We need to convert it to square meters (m²) by dividing by 1,000,000.

Given: - Cross-sectional area (A) = 0.55 mm² = 0.55 / 1,000,000 m²

Now, let's calculate the length of the nichrome wire.

Step 1: Convert the cross-sectional area to square meters: - Cross-sectional area (A) = 0.55 / 1,000,000 m²

Step 2: Calculate the length of the nichrome wire: - Length (L) = Resistance (R) x Cross-sectional Area (A) / Resistivity (ρ)

To calculate the resistivity of nichrome, we need to refer to a reliable source. Unfortunately, the search results provided by You.com do not contain the necessary information. However, I can provide you with a general range of resistivity values for nichrome.

According to reliable sources, the resistivity of nichrome typically falls within the range of