How do voltage and resistance effect the resistance of a circuit?

Question

adi3 · Answer

@Mehek14

faiqraees · Answer

Voltage and resistance of what? The battery or a resistor?

adi3 · Answer

circuit

adi3 · Answer

how does voltage and current effect the resistance of a cirut

adi3 · Answer

my bad its voltage and current not rsistance

adi3 · Answer

@FaiqRaees

faiqraees · Answer

Okay well the formula that relates voltage, current to resistance is 
$$\large\rm Resistance= \frac{Voltage}{Current} $$
From this we can see increasing the voltage will increase the resistance and increasing the current will decrease the resistance.

adi3 · Answer

so we increase voltage then we increase current right?

anonymous · Answer

Yes.

faiqraees · Answer

No, if you increase voltage the resistance will increase
and if you increase the current will decrease the resistance.

anonymous · Answer

@FaiqRaees You can rewrite it as: Current = Voltage/Resistance.

Which, when you increase voltage, means increased current.

mathmale · Answer

This is a comment to FaiqRaees:

""No, if you increase voltage the resistance will increase
and if you increase the current will decrease the resistance."

Sorry, but I disagree with this.  Increased current goes with increased voltage.  Increased current does NOT decrease resistance."

mathmale · Answer

Except with variable resistances, resistance is constant in DC circuits.

faiqraees · Answer

@mathmale It is just based on what are are keeping constant. From the question, it is evident that the change has to be reflected upon the resistance. So any change occured should have an effect on resistance

mathmale · Answer

Truly sorry to counter that, but resistance is constant, both in AC and DC circuits.  Voltage and current are both variables; resistance is not.

mathmale · Answer

The greater the current through a (fixed) resistance, the greater will be the voltage across it.

adi3 · Answer

http://prntscr.com/ae6kzg

adi3 · Answer

using this we have to answer the question

mathmale · Answer

The table shows the values of the variables voltage and current, and you are asked to calculate what the resistance is for that combo of voltage and current.  This does NOT at all imply that the resistance changes.

mathmale · Answer

You're in a lab doing measurements and need to come up with an approx value of the existing resistance in a circuit; to accomplish that you divide voltage by current.  The resistance, whatever it is, is fixed.

adi3 · Answer

so is my table wrong???

mathmale · Answer

Absolutely not.  

Voltage = current times resistance.
You have 3 quantities here:  voltage, current and resistance.

Given any two of these 3 variables, you can calculate the third, subject to common errors in measurement.

If you know the values of the voltage and the current, as given in the table, then you can determine experimentally what the (fixed) resistance is.

mathmale · Answer

If, however, you know the resistance and the current, you can calculate the voltage across the resistance.

If you know the voltage and the resistance, you can calculate the current.

adi3 · Answer

is it 100?

mathmale · Answer

Give me the voltage and the current and then I'll double check your calculation.

voltage=?

current=?

adi3 · Answer

voltage = 5
current = 0.05

mathmale · Answer

The resistance, as calculated from this data, is R = (5 volts) / (0.05 amps)  =

(500 volts) / (1 amp) = 100 ohms.  

ohms is the correct unit of measurement for resistance in this problem.

adi3 · Answer

ok thank you

mathmale · Answer

My pleasure.