What is PHP - Practice Questions & Exercises

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is PHP primarily used for?

PHP is a popular language. What is its main use?

A Managing databases directly without a server

B Designing the layout of web pages with styles

C Writing scripts that run only in the browser

D Creating dynamic web pages on the server side

💡 Hint

Think about where PHP code runs: on the server or the browser?

PHP runs on the server to create web pages that can change based on user input or data.

❓ Predict Output

intermediate

What is the output of this PHP code?

Look at this PHP code and choose the output it produces.

PHP

<?php
$number = 5;
echo $number * 2;
?>

A 5

B 10

C Error: undefined variable

D 52

💡 Hint

Multiplying 5 by 2 gives what number?

The variable $number holds 5, multiplying by 2 results in 10.

🔧 Debug

advanced

What error does this PHP code produce?

Find the error in this PHP snippet and identify the error message.

PHP

<?php
echo 'Hello World\n';
?>

A No error, outputs Hello World

B Notice: Undefined variable 'Hello World'

C Fatal error: Call to undefined function echo()

D Parse error: syntax error, unexpected end of file

💡 Hint

Check if all quotes and tags are properly closed.

The string is missing a closing quote, causing a syntax error.

📝 Syntax

advanced

Which option correctly declares a PHP variable?

Choose the correct way to declare a variable holding the number 10 in PHP.

A $num = 10;

B var num = 10;

C num = 10;

D let $num = 10;

💡 Hint

Remember PHP variables start with a special symbol.

PHP variables always start with a dollar sign ($).

🚀 Application

expert

What is the value of $result after running this PHP code?

Analyze the code and find the value stored in $result.

PHP

<?php
function add($a, $b = 3) {
  return $a + $b;
}
$result = add(4);
?>

A Error: Missing argument for function

B 4

C 7

D 3

💡 Hint

Check the default value of the second parameter.

The function adds $a and $b. $b defaults to 3 if not given, so 4 + 3 = 7.

Practice

1. What is PHP mainly used for?

easy

A. Designing static images

B. Editing videos

C. Writing desktop applications

D. Creating dynamic and interactive websites

Solution

1. Step 1: Understand PHP's purpose

   PHP is a language designed to create dynamic content on websites, making them interactive.

2. Step 2: Compare options

   Only Creating dynamic and interactive websites matches PHP's main use; others relate to different fields.

3. Final Answer:

   Creating dynamic and interactive websites -> Option D

4. Quick Check:

   PHP = Dynamic websites [OK]

Hint: PHP is for web interaction, not static or media tasks [OK]

Common Mistakes:

• Thinking PHP edits images or videos
• Confusing PHP with desktop app languages

2. Which of these is the correct way to start PHP code in a file?

easy

A. <?php

B. <script>

C. <php>

D. <?html>

Solution

1. Step 1: Recall PHP opening tags

   PHP code starts with <?php to tell the server to run PHP.

2. Step 2: Check other tags

   <script> is for JavaScript, <php> and <?html> are invalid.

3. Final Answer:

   <?php -> Option A

4. Quick Check:

   PHP code starts with <?php [OK]

Hint: PHP always starts with <?php tag [OK]

Common Mistakes:

• Using <script> instead of PHP tags
• Writing <php> which is not valid

3. What will this PHP code output?

<?php
 echo "Hello, World!";
?>

medium

A. Syntax Error

B. Hello, World!

C. <?php echo "Hello, World!"; ?>

D. Nothing

Solution

1. Step 1: Understand echo statement

   The echo command prints the text inside quotes to the browser.

2. Step 2: Check code correctness

   The code is correct PHP syntax and will output the string exactly.

3. Final Answer:

   Hello, World! -> Option B

4. Quick Check:

   echo prints text = Hello, World! [OK]

Hint: echo prints text inside quotes [OK]

Common Mistakes:

• Expecting PHP code to show as text
• Thinking code causes error without semicolon

4. Find the error in this PHP code:

<?php
 echo "Welcome to PHP!"
?>

medium

A. Echo cannot print strings

B. Wrong opening PHP tag

C. Missing semicolon after echo statement

D. Quotes should be single quotes

Solution

1. Step 1: Check PHP syntax rules

   Each statement must end with a semicolon to separate commands.

2. Step 2: Identify missing semicolon

   The echo line lacks a semicolon at the end, causing a syntax error.

3. Final Answer:

   Missing semicolon after echo statement -> Option C

4. Quick Check:

   Statements end with ; = Missing semicolon [OK]

Hint: Every PHP statement ends with a semicolon [OK]

Common Mistakes:

• Ignoring semicolon at line end
• Thinking double quotes cause error

5. You want to create a PHP page that shows the current year dynamically. Which code snippet correctly does this?

hard

A. <?php echo date('Y'); ?>

B. <?php print currentYear(); ?>

C. <?php echo 'year'; ?>

D. <?php showYear(); ?>

Solution

1. Step 1: Identify PHP function for current year

   The built-in function date('Y') returns the current year as a string.

2. Step 2: Check code snippets

   Only <?php echo date('Y'); ?> uses date('Y') correctly with echo to print the year.

3. Final Answer:

   <?php echo date('Y'); ?> -> Option A

4. Quick Check:

   date('Y') prints year = <?php echo date('Y'); ?> [OK]

Hint: Use date('Y') to get current year in PHP [OK]

Common Mistakes:

• Using undefined functions like currentYear()
• Printing literal strings instead of function output