Relationship between voltage, power and current

In summary: V x 1 A = 10 Wdouble the voltage, the current doubles as correctly stated but the power dissipated quadruples20V x 2A = 40W
  • #1
Imtiaz Ahmad
51
2
Misplaced homework thread moved here by moderator, hence no template.
Hy,
If we double the voltage than what will be double
A. power
B. Current
C. Resistance
D. Both a & b
 
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  • #2
As usual: It depends. You have not specified the context. A drawing would help.
 
  • #3
Svein said:
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
 
  • #4
Imtiaz Ahmad said:
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
 
  • #5
davenn said:
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.
 
  • #6
Imtiaz Ahmad said:
Actually problem is that
This question is on the textbook which is recommended by government.
So there is not show any circuit
 
  • #7
Imtiaz Ahmad said:
So there is not show any circuit

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

upload_2017-1-23_18-22-49.png


a nice simple one, a battery and a resistor

do you know Ohm's Law ? ...
 
  • #8
davenn said:
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
 
  • #9
Imtiaz Ahmad said:
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 :smile:
 
  • #10
davenn said:
OK, good

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

show me your working :smile:
1 A
 
  • #11
Imtiaz Ahmad said:
1 A

correct

so if you now increase the voltage to 20 V, what is the current in the circuit ?
 
  • #12
davenn said:
correct

so if you now increase the voltage to 20 V, what is the current in the circuit ?
2 A
 
  • #13
Imtiaz Ahmad said:
2 A

correct :smile:

so next, what is the formula for finding power ?
 
  • #14
davenn said:
correct [emoji2]
so next, what is the formula for finding power ?
P = I V
P= I (2) R
P = V (2) / R
 
  • #15
Imtiaz Ahmad said:
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 ...

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

Dave
 
  • #16
davenn said:
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
 
  • #17
Imtiaz Ahmad said:
Mean D option is correct

yes, well done :smile:

wasn't too difficult to work out, huh :wink:
.

Dave
 
  • #18
davenn said:
yes, well done [emoji2]
wasn't too difficult to work out, huh :wink:
.

Dave
Thanks
But
Is this answer corrected. If current is double
P = 2 I * 2 V
 
  • #19
Imtiaz Ahmad said:
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
 
  • #20
davenn said:
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?
 
  • #21
Mean energy loss
 
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  • #22
Imtiaz Ahmad said:
Power dissipated mean?

power lost, radiated, used up <---- take your pick, all the same :smile:
 
  • #23
davenn said:
power lost, radiated, used up <---- take your pick, all the same :smile:
[emoji3]
 
  • #24
I moved it to homework, where it better fits and can be found by others with similar questions.
 
  • #25
Imtiaz Ahmad said:
Mean D option is correct
Check again the amount by which current and power changed. They don't change by the same factor.
 
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  • #26
gneill said:
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 :wink: :rolleyes:

@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
 
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  • #27
davenn said:
I royally screwed up ... I blame old age and senility :wink: :rolleyes:

@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
 
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  • #28
Imtiaz Ahmad said:
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
 
  • #29
Imtiaz Ahmad said:
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
 

FAQ: Relationship between voltage, power and current

1. What is the relationship between voltage, power, and current?

The relationship between voltage, power, and current can be described by Ohm's law, which states that voltage (V) is equal to the product of current (I) and resistance (R), or V = I x R. This means that an increase in voltage will result in an increase in power, while an increase in resistance will result in a decrease in current.

2. How are voltage, power, and current measured?

Voltage is measured in volts (V), power is measured in watts (W), and current is measured in amperes (A). These measurements can be obtained using specialized instruments such as a voltmeter, wattmeter, and ammeter, respectively.

3. What happens to power when voltage or current changes?

If either voltage or current changes, power will also change. The relationship between voltage, current, and power is linear, meaning that a change in one will result in a proportional change in the other.

4. Can voltage, power, and current be converted into each other?

Yes, voltage, power, and current can be converted into each other using Ohm's law. For example, if the voltage and resistance are known, power can be calculated by dividing voltage by resistance. Similarly, if the current and resistance are known, voltage can be calculated by multiplying current by resistance.

5. How does the relationship between voltage, power, and current affect electrical circuits?

The relationship between voltage, power, and current is crucial in understanding and designing electrical circuits. By controlling voltage and resistance, the flow of current can be regulated, which in turn affects the amount of power used by the circuit. This is important in preventing damage to electrical components and ensuring efficient use of energy.

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