A total charge of 25 mC passes through a cross-sectional area of a nichrome wire in 10 s. What is the current in the wire?
Choose one answer.
a. 2.5 A
b. 2.5 mA
c. 25 mA
d. 2.5 µA
c. 25 mA
To find the current in the wire, we can use the formula:
Current = Charge / Time
Given that the total charge passing through the wire is 25 mC (milli-Coulombs) and the time is 10 s, we can substitute these values into the formula:
Current = 25 mC / 10 s
To simplify the calculation, let's convert the charge from milli-Coulombs to Coulombs:
25 mC = 25 x 10^(-3) C
Substituting this value into the formula:
Current = (25 x 10^(-3) C) / 10 s
Simplifying the expression:
Current = 2.5 x 10^(-3) C / 10 s
Simplifying further, we can divide both the numerator and denominator by 10:
Current = 2.5 x 10^(-4) C / s
Since the unit for current is Ampere (A), we can rewrite this in scientific notation:
Current = 2.5 x 10^(-4) A
Converting back to decimal notation, the current in the wire is 0.00025 A.
Therefore, the correct answer is:
d. 2.5 µA (micro-Amperes)
To find the current in the wire, we can use the formula:
Current = Total charge / Time
Given that the total charge passing through the wire is 25 mC and the time is 10 s, we can substitute these values into the formula:
Current = 25 mC / 10 s
To perform the calculation, we need to convert the milliampere (mC) to ampere (A):
1 A = 1000 mA
Converting 25 mC to A:
25 mC = 25 / 1000 A = 0.025 A
Now we can substitute the converted value back into the formula:
Current = 0.025 A / 10 s
Simplifying the calculation:
Current = 0.0025 A
Since 0.0025 A is equivalent to 2.5 mA, the correct answer is option b. 2.5 mA.