calculate the value of the resistor approximately?

Question

the value of of a resistor is measured by the voltmeter-ammeter method. the internal resistance of the voltmeter is 200ohms. when the voltmeter is connected directly across the resistance to be measured, then the ammeter reads 10a and voltmeter 100v

Answer 1

The ammeter will measure the total current through both the resistor and the voltmeter. Voltmeter measures the voltage across both. If that voltage is V, then the ammeter current reading will be

V/R + V/200 = I

1/R + 1/200 = I/V

1/R = I/V - 1/200

R = 1 / [I/V - 1/200]

If I = 10 A and V = 100 V then I/V = 0.1; 1/200 = 0.005

0.1 - 0.005 = 0.095

1/0.095 = 10.53 ohms

Answer 2

It looks to me like there are some errors in copying the question.
I suspect that the internal resistance of the _ammeter_ is 200Ω, not the voltmeter, then, as the first answerer said, 10mA would seems more likely (since it would take 2000V to force 10A through the meter alone)

If the current is 10mA and the meter (in series with the load) is 200Ω then (unknown resistor + 200) = 1000V / 0.01A; so the unknown resistor is 9800ohm, 9.8kohm

[EDIT] has anyone here ever seen a voltmeter dissipates 50 watts while measuring 100volts? Granted, a 200Ω shunt is a little high for 10mA too, but I think the 200Ω voltmeter makes less sense, though if that really is the case, a couple other people have worked out the resistor value.

Answer 3

The total current for the circuit is 10A
the voltage across the voltmeter is 100V
The current through the meter is 100/200=0.5A
The current through the unknown resister is 10A-0.5A=9.5A
Resistor =100V/9.5A=10.526 Ohms

Answer 4

once you reported "turn alerts - i assume you've an automobile software in thoughts... hence, the voltage you'd be operating with is 12 V. first of all, the voltage for the white LED is likely incorrect... My wager is the voltage is closed to three.2 V... i'd placed 3 of each and every LED in series, so for white the total voltage is in all probability to be 9.6 V and for amber the voltage is in all probability to be 7.5 V... So, the voltage to drop is 12 - 9.6 = 2.4 V (for white) and 12 - 7.5 = 4.5 V (for amber)... E = I x R or... R = E / I R = 2.4V / 0.02A = 100 and twenty Ohms (for white)... R = 4.5V / 0.02A = 225 Ohms (for amber)... to apply more advantageous than 3 LEDs merely placed the series strings of three LEDs and one resistor in parallel... do not connect the series LEDs in parallel with in easy words one resistor...

Answer 5

Voltage = Current X Resistance
100V=10a X R
100/10 = R
R =10 Ohms

Although you probably meant that the current was 10 mA
100/10milli = R
R=10000=10KOhms