In the series circuit, a certain value of resistance is 10 Ω, the maximum resistance of sliding rheostat is 50 Ω, and the power supply voltage is 6 v. the maximum power of sliding rheostat is calculated

In the series circuit, a certain value of resistance is 10 Ω, the maximum resistance of sliding rheostat is 50 Ω, and the power supply voltage is 6 v. the maximum power of sliding rheostat is calculated

In fact, the high school physics teacher said that when the constant resistance is equal to the sliding rheostat resistance, the power of the sliding rheostat is the maximum. If the sliding rheostat resistance is r, the power is the maximum, then I = 6 / (10 + R) P = I ^ 2R = 36R / (10 + R) ^ 2, derivative = (- 36R ^ 2 + 3600) / (10 + R) ^ 4, let P ~ = 0 get r = 10 ohm, then p is the most

Connect a 15 ohm resistance to a 3V power supply. When Xiao Wu uses an ammeter with two ranges of 0 to 0.6A and 0 to 3a to measure the current passing through the resistance, the indication is 1.0A. The reason for the error is that
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Big brother, there is only one conclusion. Xiao Wu read the wrong number
First, the actual current is I = 3 / 15 = 0.2A
0.6A gear 0A 0.1A 0.2A 0.3A 0.4A 0.5A 0.6A
3A gear 0A 0.5A 1.0A 1.5A 2.0A 2.5A 3.0A
The actual current is 0.2A, and should be read from 0 to 0.6A,
He read 0-3.0a, which corresponds to 1.0A

There are three resistors with resistance values of 3, 6 and 9 respectively. If they are connected in series and connected to a 6V power supply, the voltages of the three resistors are?

First find out the total resistance of the circuit, and then find out the total current, and then according to Ohm's Law (known current and resistance) to find out the voltage on each resistor!

When a 24 ohm resistor is connected to a circuit, the current in the circuit is 0.5 A, and the power supply voltage is constant
1 power supply voltage
2. Connect resistor R2 in series with the resistor, and the current in the circuit drops to 0.2 A. what is the resistance value of R2?

1》 When the power supply capacity is large enough, the power supply voltage is basically unchanged after the load is connected
Power supply voltage:
U＝RI＝24×0.5＝12(V)
2》 Voltage at both ends of 24 ohm resistor when 2 resistors are in series:
U＝RI＝24×0.2＝4.8(V)
R2 resistance value:
R＝U/I＝(12－4.8)/0.2＝36(Ω)