Question 1: Explain what a file mode 'r' signifies when opening a file in a programming language like Python.

Answer: The mode 'r' signifies that the file is being opened for reading only.

Question 2: Write a short code snippet in Python that opens a file called 'data.txt' for writing, writes the text 'Hello World', and then closes the file.

Answer: with open('data.txt', 'w') as file: file.write('Hello World')

Question 3: Describe what happens if you try to read from a file that has been opened in write-only mode.

Answer: Attempting to read from a file opened in write-only mode will result in an error because the file is not opened for reading.

Question 4: Complete the truth table for the AND gate with inputs A and B, and output Q.

Answer: A | B | Q --|---|-- 0 | 0 | 0 0 | 1 | 0 1 | 0 | 0 1 | 1 | 1

Question 5: Draw the logic circuit for an OR gate using standard logic symbols. Label the inputs and output clearly.

Answer: A standard OR gate is a curved shape with two inputs entering on the left side and a single output on the right. The shape resembles a shield or a pointed oval with the inputs labelled A and B, and the output labelled Q.

Question 6: Sketch a truth table for a NOT gate with a single input A and output Q. The table should include all possible input-output combinations.

Answer: A | Q --|-- 0 | 1 1 | 0

Question 7: A program needs to check if a user has entered the correct password. The program reads the input from a file. Describe the steps the program should take to verify the password stored in the file.

Answer: The program should open the file in read mode, read the stored password from the file, compare it with the user’s entered password, and then close the file. If they match, grant access; otherwise, deny access.

Question 8: Complete the truth table for an XOR gate with inputs A and B, and output Q.

Answer: A | B | Q --|---|-- 0 | 0 | 0 0 | 1 | 1 1 | 0 | 1 1 | 1 | 0

Question 9: Draw a logic circuit that combines an AND gate and a NOT gate so that the output is true only when A is true and B is false. Label all inputs and the final output.

Answer: Draw an AND gate with inputs A and B, then connect its output to the input of a NOT gate. The output of the NOT gate is the final output, which is true only when A is true and B is false.

Question 10: Explain the difference between 'read' and 'write' modes when handling files in programming.

Answer: 'Read' mode allows a program to access and retrieve data from a file without modifying it. 'Write' mode enables a program to create a new file or overwrite existing data in a file.

Question 11: Describe what a 'file pointer' is and how it is used when reading from or writing to a file.

Answer: A file pointer is a position indicator within a file that shows where the next read or write operation will occur. It moves forward as data is read or written, allowing sequential access to the file's contents.