In the circuit as shown in the figure, the resistance R1 of lamp L1 is half of the resistance R2 of lamp L2 (regardless of the change of filament resistance with temperature), and the power supply voltage is 10V. When the switches S0 and S1 are closed and the switches S2 are disconnected, the lamp L1 lights normally, the electric power consumed by the resistance R3 is 2W, and the voltage expression number is U1; when the switches S2 are closed and the switches S1 and S0 are disconnected, the electric power consumed by the resistance R4 is 0.25W, The number of voltage is half U1. Calculate: (1) the ratio of two readings of ammeter; (2) the rated electric power of lamp L1; (3) the resistance of resistor R4

In the circuit as shown in the figure, the resistance R1 of lamp L1 is half of the resistance R2 of lamp L2 (regardless of the change of filament resistance with temperature), and the power supply voltage is 10V. When the switches S0 and S1 are closed and the switches S2 are disconnected, the lamp L1 lights normally, the electric power consumed by the resistance R3 is 2W, and the voltage expression number is U1; when the switches S2 are closed and the switches S1 and S0 are disconnected, the electric power consumed by the resistance R4 is 0.25W, The number of voltage is half U1. Calculate: (1) the ratio of two readings of ammeter; (2) the rated electric power of lamp L1; (3) the resistance of resistor R4

For the first time, close switch S0 and S1, and open switch S2: at this time, L1 and R3 are in series. (L4 and R4 are not connected to the circuit and do not work)
Current I1 = U1 / R1
U1=I1R1,U3=U-U1=10-U1
R3 power P3 = i1u3 = (U1 / R1) * (10-u1) = 2W. ①
For the second time, close switch S2 and disconnect switches S1 and S0: L1, L2 and R4 are connected in series. (R3 does not work when current is not connected)
Current I2 = U1 '/ R1 = 0.5u1/r1
U2=I2R2=I2*2R1=2*(0.5U1/R1)*R1=U1
U4=U-U1'-U2=10-0.5U1-U1=10-1.5U1
The power of R4 is P4 = i2u4 = (0.5u1 / R1) * (10-1.5u1) = 0.25W
Therefore, I 1: I 2 = 1:0.5 = 2:1
① (2) U1, R1
I1 = U1 / R1 also know
The power of lamp L1 is P1 = u1i1
I2 = 0.5i1
The value of resistance R4 R4 = P4 / (I2 Square) is also known
It's too troublesome to calculate and type

In general, how does the resistance of a conductor change with temperature

Generally, the resistance of conductor increases with the increase of temperature

How does resistance change with temperature
Why does the thermistor decrease with the increase of temperature, but when measuring the resistance by voltammetry, the higher the voltage is, the smaller the resistance is? How does the resistance change with the change of temperature?

Ordinary resistance will increase with the increase of temperature, but the thermistor is made of semiconductor, and the change of resistance of semiconductor is just opposite to that of ordinary conductor