The rheostat was made from nichrome wire 50 m long with a cross-sectional area of 1 mm2

The rheostat was made from nichrome wire 50 m long with a cross-sectional area of 1 mm2, find the voltage if the current strength is 4A.

Task data: l (length of the used nichrome wire) = 50 m; S (cross-sectional area of the wire) = 1 mm2; I (current in the manufactured rheostat) = 4 A.

Reference values: ρ (specific electrical resistance of nichrome at 20 ºС) = 1.1 Ohm * mm2 / m.

The voltage on the manufactured rheostat is determined by the formula: U = I * R = I * ρ * l / S.

Let’s calculate: U = 4 * 1.1 * 50/1 = 220 V.

Answer: The voltage on the manufactured rheostat will be 220 V.