An electric device delivers a current of [tex]$15.0 A$[/tex] for 30 seconds. How many electrons flow through it?
Answer (2)
A current of 15.0 A flowing for 30 seconds results in a total charge of 450 C . This is equivalent to approximately 2.81 × 1 0 21 electrons flowing through the device. The charge of a single electron is approximately 1.6 × 1 0 − 19 C .
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25%
Explanation
Understanding the Problem Let's break down how to calculate the credit lost for a wrong answer on a multiple-choice question.
Identifying the Variables The problem states that if you answer a multiple-choice question incorrectly, you lose n − 1 1 of the credit, where n is the number of answer choices. In this case, there are 5 answer choices, so n = 5 .
Calculating the Credit Lost as a Fraction Now, we can calculate the fraction of credit lost by substituting n = 5 into the formula: n − 1 1 = 5 − 1 1 = 4 1 .
Converting to Percentage To express this as a percentage, we multiply the fraction by 100: 4 1 × 100% = 25% .
Final Answer Therefore, if you submit one wrong answer before getting the question correct, you will lose 25% of the credit for that question.
Examples
Imagine you're taking a quiz with multiple-choice questions, and each question is worth a certain number of points. Knowing how much you'll lose for a wrong answer helps you decide whether to guess or skip the question. For example, if you're not sure of the answer but can eliminate a couple of choices, it might be worth guessing. Understanding these penalties can improve your test-taking strategy and help you maximize your score. This is also applicable in scenarios like online quizzes or surveys where incorrect responses might lead to a deduction.
