When the voltage applied at both ends of a resistor is 5V, the current passing through it is 0.5A. To make the current passing through the resistor 1a, add it to both ends of the resistor What is the voltage applied at both ends of the resistor? If the voltage at both ends increases to 20V, what is the resistance of the resistor? What is the current passing through it?

When the voltage applied at both ends of a resistor is 5V, the current passing through it is 0.5A. To make the current passing through the resistor 1a, add it to both ends of the resistor What is the voltage applied at both ends of the resistor? If the voltage at both ends increases to 20V, what is the resistance of the resistor? What is the current passing through it?

First calculate its resistance value r = 5 / 0.5 = 10 Ω. When the current passing through the resistor is 1a, the voltage at both ends is u = I * r = 1 * 10 = 10V. If the voltage at both ends increases to 20V, the resistance value of the resistor is 10 Ω, but the current passing through it is I = u / r = 20 / 10 = 2A

When the voltage at both ends of a fixed value resistor is 4V, the current passing through is 0.5A. If the voltage at both ends of the resistor increases to 5V, the rest is in the supplement
Can we use an ammeter with a range of 0 ~ 0.6A to measure the current?

First there is Ohm's theorem to the resistance value, 8 ohm In the same way, we get the current It seems to be greater than 0.6A In addition, it is better to make the pointer at 2 / 3 of the whole range for pointer type instruments

The voltage at both ends of the power supply is u = 4.5V and the resistance remains unchanged R1 = 5 Ω. The maximum resistance of the rheostat R2 is 20 Ω, the range of the ammeter is 0-0.6a, and the range of the voltmeter is 0-3v. What is the resistance range of the rheostat access circuit to protect the ammeter
Note: no drawing
Circuit description: resistor and rheostat in series, voltmeter and rheostat in parallel, ammeter in series into the circuit

The range of ammeter is 0-0.6a, the maximum current I = 0.6A, the corresponding resistance R = u / I = 4.5v/0.6a = 7.5 Ω, R2 = r-r1 = 7.5 Ω - 5 Ω = 2.5 Ω, the range of voltmeter is 0-3v, U2 = 3V, U1 = u-u2 = 4.5v-3v = 1.5V, series partial voltage U1 / U2 = R1 / R2, i.e. 1.5v/3v = 5 Ω / r2r2 = 10 Ω

When 5V voltage is applied at both ends of a resistor, the current passing through it is 0.5A; when 8V voltage is applied at both ends, the current passing through it is -------- a

0.8 amp