Using the definition of electric current, what is the current in amperes when a charge of 500 coulomb flows uniformly through a conductor in 25 seconds?

Introduction / Context:
This question is a straightforward numerical application of the definition of electric current. Current represents the rate of flow of electric charge through a conductor. If you know how much charge passes through a cross section in a certain time, you can calculate the current easily. Such calculations are common in basic electricity and electronics problems.

Given Data / Assumptions:

• Total charge flowing, Q = 500 coulomb.
• Time of flow, t = 25 seconds.
• Charge is assumed to flow uniformly during this interval.
• We are asked to find the electric current I in ampere.

Concept / Approach:
Electric current I is defined as the rate of flow of charge, given by the formula I = Q / t, where Q is the total charge in coulomb and t is the time in second. One ampere corresponds to one coulomb of charge passing through a cross section in one second. Substituting the given values into the formula allows a simple division to find the current. Care must be taken to divide correctly and to interpret the result as an ampere value, not a raw number without units.

Step-by-Step Solution:
Step 1: Write the formula for current: I = Q / t. Step 2: Substitute the given values: Q = 500 C and t = 25 s. Step 3: Compute I = 500 / 25. Step 4: Perform the division: 25 goes into 50 two times, leaving 0, so 500 / 25 = 20. Step 5: Attach the correct unit: I = 20 ampere (A). Step 6: Compare with the options and see that 20 is listed as option B. Step 7: Conclude that the current is 20 A.

Verification / Alternative check:
As a quick mental check, note that 25 seconds is one quarter of 100 seconds. If 500 coulomb passes in 25 seconds, then in 100 seconds at the same rate, 2000 coulomb would pass. The current would then be 2000 C / 100 s = 20 A, which matches the answer. Another way to see it is that 500 / 25 equals 50 / 2.5, which is 20. These quick checks confirm that the arithmetic is correct and that 20 A is reasonable for many circuits.

Why Other Options Are Wrong:
12500 ampere would correspond to 500 C flowing in 0.04 s, which is much larger than the given time and clearly not correct for the data. 40 ampere would imply 500 C in 12.5 s, not in 25 s, so it does not satisfy the given conditions. 6250 ampere would imply 500 C in 0.08 s, which again is inconsistent with 25 s.

Common Pitfalls:
Common mistakes include inverting the formula to t / Q instead of Q / t or misplacing decimal points when dividing. Another error is forgetting to include units in the answer. Always start by writing I = Q / t, then substitute values carefully and carry the unit ampere through to the final result. Double checking the division mentally can help avoid simple calculation errors in an exam setting.

Final Answer:
The current is 20 ampere when 500 coulomb of charge flows in 25 seconds.