Calculate Current Drawing at 120V After 15.8% Voltage Reduction

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In summary, the question asks for the current drawn at 120 V if the resistance of the device is reduced by 15.8%. Using the equation 120/(0.842 x 46.875), the result is approximately 16 A.
  • #1
shimizua
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Homework Statement


If the resistance of the device were reduced by 15.8 percent, what current would be drawn at 120 V?

there was a first part of this question which i have already gotten. the question was
An electrical device draws 2.56 A at 120 V. If the voltage drops by 15.8 percent, what will be the current, assuming nothing else changes? so the resistance is 46.875


Homework Equations


ok so i believe that i would just do 120/(.158x46.875)


The Attempt at a Solution


when i did this i got like 16 A and it was said to be wrong. i am confused on what i did wrong.
 
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  • #2
Reducing by 15% means you keep 85% of the resistance. Multiply by .842, not .158.
 
  • #3


Your attempt at a solution is correct. The equation you used, V/R = I, is the correct formula for calculating current when voltage and resistance are known. In this case, you correctly substituted in the new resistance value (46.875) and the original voltage (120V). Your answer of 16 A also seems reasonable, as a decrease in resistance would result in an increase in current.

It is possible that there was a mistake in the previous part of the question, where the voltage was reduced by 15.8%. If the voltage was actually reduced by a different percentage, it would affect the final answer. It is also possible that there was a rounding error or a mistake in the units used in the calculation. Double-checking your work and the given information may help to identify any errors. Overall, your approach and solution seem correct.
 

Related to Calculate Current Drawing at 120V After 15.8% Voltage Reduction

1. What is the formula for calculating current after a 15.8% voltage reduction?

The formula for calculating current after a 15.8% voltage reduction is I = V/R, where I is the current, V is the voltage, and R is the resistance.

2. How do you determine the voltage reduction percentage?

The voltage reduction percentage can be determined by subtracting the reduced voltage from the original voltage, dividing that by the original voltage, and then multiplying by 100.

3. Can the current be calculated without knowing the resistance?

No, the current cannot be calculated without knowing the resistance. The resistance is a necessary component in the formula for calculating current.

4. What is the significance of using 120V in the calculation?

Using 120V in the calculation is significant because it is the standard voltage for most household electrical outlets in the United States. This makes it a commonly used value for calculating current in household appliances and electronics.

5. How does a voltage reduction affect the current drawn?

A voltage reduction will result in a decrease in the current drawn, as shown by the formula I = V/R. This is because the lower voltage will result in a lower potential difference, which in turn will result in a lower current flowing through the circuit.

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