Relationship between voltage, power and current

[Imtiaz Ahmad]

Hy,
If we double the voltage than what will be double
A. power
B. Current
C. Resistance
D. Both a & b

 

[Svein]

As usual: It depends. You have not specified the context. A drawing would help.

 

[Imtiaz Ahmad]

As usual: It depends. You have not specified the context. A drawing would help.

When we double the voltage in a simple electric circuit, we double the
A. Current
B. Power
C. Resistance
D. Both current and power

 

[davenn]

When we double the voltage in a simple electric circuit, we double the

you still haven't specified the circuit setup
until you fix (state) a couple of the variables, your Q cannot be answered

Dave

 

[Imtiaz Ahmad]

you still haven't specified the circuit setup
until you fix (state) a couple of the variables, your Q cannot be answered

Dave

Actually problem is that
This question is on the textbook which is recommended by government.

 

[Imtiaz Ahmad]

Actually problem is that
This question is on the textbook which is recommended by government.

So there is not show any circuit

 

[davenn]

So there is not show any circuit

so, so let me provide you with a circuit ...

a nice simple one, a battery and a resistor

do you know Ohm's Law ? ...

 

[Imtiaz Ahmad]

so, so let me provide you with a circuit ...

View attachment 111995

a nice simple one a battery and a resistor

do you know Ohm's Law ? ...

Yes I know

 

[davenn]

Yes I know

OK, good

so you have 10V across a 10 Ohm resistor ...
what is the current flowing in that circuit ?

show me your working

 

[Imtiaz Ahmad]

OK, good

so you have 10V across a 10 Ohm resistor ...
what is the current flowing in that circuit ?

show me your working

1 A

 

[davenn]

1 A

correct

so if you now increase the voltage to 20 V, what is the current in the circuit ?

 

[Imtiaz Ahmad]

correct

so if you now increase the voltage to 20 V, what is the current in the circuit ?

2 A

 

[davenn]

2 A

correct

so next, what is the formula for finding power ?

 

[Imtiaz Ahmad]

correct [emoji2]
so next, what is the formula for finding power ?

P = I V
P= I (2) R
P = V (2) / R

 

[davenn]

P = I V
P= I (2) R
P = V (2) / R

Yup
for ease we can use your first choice P = I x V

work out the two power levels for the examples we have just done

then answer your original Q ...

Hy,
If we double the voltage than what will be double
A. power
B. Current
C. Resistance
D. Both a & b

Dave

 

[Imtiaz Ahmad]

Yup
for ease we can use your first choice P = I x V

work out the two power levels for the examples we have just done

then answer your original Q ...
Dave

Mean D option is correct

 

[davenn]

Mean D option is correct

yes, well done

wasn't too difficult to work out, huh
.

Dave

 

[Imtiaz Ahmad]

yes, well done [emoji2]
wasn't too difficult to work out, huh
.

Dave

Thanks
But
Is this answer corrected. If current is double
P = 2 I * 2 V

 

[davenn]

Is this answer corrected. If current is double

unlike voltage or resistance, current cannot just change
current is a RESULT of a given voltage across a given resistance
That is, current can ONLY change IF the voltage OR the resistance changes

And the power, in Watts, dissipated in a circuit, in our circuits above ( in the resistor)
is always related to the voltage across the resistance divided by the resistance

so for a fixed resistance, if the voltage is doubled, then the current is doubled and therefore so is the power dissipatedDave

 

[Imtiaz Ahmad]

unlike voltage or resistance, current cannot just change
current is a RESULT of a given voltage across a given resistance
That is, current can ONLY change IF the voltage OR the resistance changes

And the power, in Watts, dissipated in a circuit, in our circuits above ( in the resistor)
is always related to the voltage across the resistance divided by the resistance

so for a fixed resistance, if the voltage is doubled, then the current is doubled and therefore so is the power dissipatedDave

Power dissipated mean?

 

[Imtiaz Ahmad]

Mean energy loss

 

[davenn]

Power dissipated mean?

power lost, radiated, used up <---- take your pick, all the same

 

[Imtiaz Ahmad]

power lost, radiated, used up <---- take your pick, all the same

[emoji3]

 

[fresh_42]

I moved it to homework, where it better fits and can be found by others with similar questions.

 

[gneill]

Mean D option is correct

Check again the amount by which current and power changed. They don't change by the same factor.

 

[davenn]

Check again the amount by which current and power changed. They don't change by the same factor.

I royally screwed up ... I blame old age and senility

@imtiaz ... humble apologies answer b) current ... should have been answer

for power

10V x 1 A = 10 W

double the voltage, the current doubles as correctly stated but the power dissipated quadruples

20V x 2A = 40W

@gneill ... cheersDave

 

[Imtiaz Ahmad]

I royally screwed up ... I blame old age and senility

@imtiaz ... humble apologies answer b) current ... should have been answer

for power

10V x 1 A = 10 W

double the voltage, the current doubles as correctly stated but the power dissipated quadruples

20V x 2A = 40W

@gneill ... cheersDave

So current is correct

 

[Imtiaz Ahmad]

Hy,
If we double the voltage than what will be double
A. power
B. Current
C. Resistance
D. Both a & b

If circuit is simple

 

[Imtiaz Ahmad]

Hy,
If we double the voltage than what will be double
A. power
B. Current
C. Resistance
D. Both a & b

If circuit is double