An electric device delivers a current of [tex]$15.0 A$[/tex] for 30 seconds. How many electrons flow through it?
Answer (2)
The correct answer is C because a nested if statement is an if statement inside another if statement. Option A is syntactically incorrect. Option B is a simple if-else statement. Option D has syntax errors. Therefore, the answer is C .
Explanation
Understanding Nested if Statements We need to identify which of the given options represents a nested if statement. A nested if statement is simply an if statement that appears within another if statement. Let's examine each option to determine which one fits this description.
Analyzing Option A Option A: if(if(expression)) {code} This is not a valid nested if statement because the inner if lacks a condition. The syntax is incorrect.
Analyzing Option B Option B: if(expression) {code} else {code} This is a simple if-else statement. It's not nested because there's no if statement inside another if statement.
Analyzing Option C Option C: if(expression) {if(expression) {code}} This is a valid nested if statement. The inner if statement is located within the code block of the outer if statement.
Analyzing Option D Option D: if(expression) (code) if(expression) {code} This is not a valid nested if statement due to syntax errors. The (code) part is not correctly placed, and it doesn't form a proper nested structure.
Conclusion Based on the analysis, option C correctly represents a nested if statement.
Examples
Nested if statements are useful in scenarios where multiple conditions need to be checked sequentially. For example, consider a program that determines a student's grade based on their score. First, it checks if the score is greater than or equal to 60. If it is, then it checks if the score is greater than or equal to 70, 80, 90, etc., to assign a specific grade (e.g., A, B, C). Each subsequent check is nested within the previous one, allowing for a detailed evaluation of the student's performance.
The device delivers a charge of 450 coulombs with a current of 15.0 A over 30 seconds. This charge corresponds to approximately 2.81 x 10^21 electrons flowing through it. Thus, a vast number of electrons pass through the device in that time period.
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