12.5 Coulombs of charge flows through a 5 kilo-ohm resistor in 8 minutes. (a) What is the electric current that flows througt the resistor? (b) How muc power is consumed by the rsistor?
2)
A 15 m long copper wire has a cross- sectional radius of 3 mm. (a) What is the resistance of the wire ?(r= 1.68*10-8Ohm*m )
2)
A 15 m long copper wire has a cross- sectional radius of 3 mm. (a) What is the resistance of the wire ?(r= 1.68*10-8Ohm*m )
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Verified answer
Ответ:
Объяснение:
1)
t = 8 мин = 480 с
Ток:
I = q/t = 12,5/480 = 0,025 A
P = I²·R = 0,025²·5000 ≈ 3 Вт
2)
S = π·R² = 3,14·(3·10⁻³)² ≈ 28·10⁻⁶ м²
R = ρ·L/S = 1,68·10⁻⁸·15 / (28·10⁻⁶) ≈ 0,009 Ом