The voltage across a lamp is (6.0± 0.1) volt and the current passing through it is (4.0± 0.2) ampere. Find the power consumed.
Correct Answer :
(24.0± 1.6) watt
Solution :
The correct option is (24.0± 1.6) watt.
Step 1: Calculate the nominal power consumed.
The power consumed by an electrical component is given by the formula:
where:
- Voltage,
- Current,
Substituting the nominal values into the equation:
Step 2: Calculate the error in power.
For a product of two quantities, the relative error in the result is the sum of the relative errors of the individual quantities:
where:
- Absolute error in voltage,
- Absolute error in current,
Substitute the values to find the fractional error in power:
Find a common denominator to sum the fractions:
Now, solve for the absolute error in power :
Step 3: Express the final result with error limits.
Combining the nominal power and its absolute error:
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