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A quick solution to the problem of electrical calculation in physics in grade two of junior high school The resistance r1r2 is in parallel. The electric power of R1 is 0.6W. The resistance of R2 is 15. The main circuit current is 0.5A. Calculate the resistance of R1 and the voltage U
Current I1 = P / u = 0.6/u in R1
Current I2 = u / r2 = u / 15 in R2
Main circuit current I = I1 + I2 = (0.6 / U) + (U / 15) = 0.5
The solution is: u = 1.5V or u = 6V
The corresponding calculation shows that R1 = 3.75 Ω or R1 = 60 Ω
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Fast solution to electrical calculation problems in physics in grade two of junior high school
An 8 ohm resistor is connected in parallel with another resistor, connected in 24 V, and the main current is 9 a. calculate the resistance value of the second resistor and the power consumed
From the current voltage relationship of parallel circuit, 1 / r = 1 / R1 + 1 / R2 (1) and R = u / I, r = 24 / 9 is obtained
Take r = 24 / 9 into (1) to get 9 / 24 = 1 / 8 + 1 / R2 and R2 = 4
From P = u ^ 2 / R, we get P = 24 ^ 2 / 4 = 144
That is, the resistance is 4 and the power is 144
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