One resistor is 10 ohm and the other is 2 ohm. Connect these two resistors to the 12V circuit. What is the power of the first resistor

One resistor is 10 ohm and the other is 2 ohm. Connect these two resistors to the 12V circuit. What is the power of the first resistor

If connected in series to 12V circuit, the total resistance R = R1 + R2 = 12 Ω, the current is I = u / r = 12V / 12 Ω = 1a
P1=U1I=I²R1=(1A)²*10Ω=10w
If in parallel, P1 = u1i1 = u & # 178 / R1 = (12V) &# 178 / 10 Ω = 14.4w

The range of voltmeter is 15V, and a 500ohm resistor is connected in series. When measuring the voltage at both ends of a circuit, the indication is 12V, and the actual voltage of the circuit is 15V
If the voltmeter is changed to a voltmeter with a range of 0 ~ 100V, the resistance value of the series resistance should be calculated
In a hurry

When a 500 ohm resistor is connected in series to measure the voltage at both ends of a circuit, the indication is 12V and the actual voltage of the circuit is 15V
U resistance = u total - U meter = 15-12 = 3V
I = I resistance = u resistance / r = 3 / 500 a
R table = u table / I = 12 * 500 / 3 = 2000 Ω
When u meter = 15V, full bias
I full deviation = u full deviation / R table = 15 / 2000 a
If it is changed to a voltmeter with a range of 100V, a resistor R 'should be connected in series
U resistance = 100-u full deflection = 100-15 = 85V
R resistance = u resistance / I full deviation = 85 * 2000 / 15 = 11333.3 Ω