Question 1: Describe the main stages involved in the fetch-execute cycle of a CPU.

Answer: The main stages are: 1. Fetch: retrieving an instruction from memory, 2. Decode: interpreting the instruction, 3. Execute: performing the operation specified by the instruction, 4. Repeat: cycle continues for the next instruction.

Question 2: Explain why the fetch-execute cycle is essential for a computer to run programs.

Answer: It allows the CPU to systematically retrieve, interpret, and perform instructions stored in memory, enabling programs to run step-by-step automatically.

Question 3: List the main components involved in the fetch phase of the cycle.

Answer: The Program Counter (PC), the Memory Address Register (MAR), the Memory Data Register (MDR), and the instruction register.

Question 4: What role does the Program Counter (PC) play in the fetch process?

Answer: It holds the address of the next instruction to be fetched from memory and is updated after each fetch to point to the subsequent instruction.

Question 5: Draw a diagram showing the flow of data during the fetch phase of the cycle. Label all components involved.

Answer: A diagram illustrating the Program Counter sending an address to Memory, data returning to MDR, and then moving to the instruction register, with labels for each component.

Question 6: Complete the truth table for an AND logic gate with two inputs, A and B, and one output, Q.

Answer: [{"A":0,"B":0,"Q":0},{"A":0,"B":1,"Q":0},{"A":1,"B":0,"Q":0},{"A":1,"B":1,"Q":1}]

Question 7: Draw the logic circuit for an OR gate using basic logic symbols. Label all inputs and the output.

Answer: A diagram showing two input variables connected to an OR gate symbol, with the output labeled as Q.

Question 8: Identify the logic gate that outputs true only when exactly one of its inputs is true.

Answer: The XOR (exclusive OR) gate.

Question 9: A circuit contains two switches connected to an AND gate. Describe how the circuit behaves when both switches are turned on and when only one is on.

Answer: When both switches are on, the AND gate outputs true (1). If only one switch is on, the output is false (0).

Question 10: Sketch a truth table for a NAND gate with two inputs, A and B.

Answer: [{"A":0,"B":0,"Q":1},{"A":0,"B":1,"Q":1},{"A":1,"B":0,"Q":1},{"A":1,"B":1,"Q":0}]

Question 11: Explain how a NOT gate functions and give an example of its use in a digital circuit.

Answer: A NOT gate outputs the opposite value of its input; if the input is 1, the output is 0, and vice versa. It is used for inverting signals, such as turning a high signal into a low signal.

Question 12: Describe a scenario where the fetch-execute cycle might be interrupted and explain how the CPU handles such interruptions.

Answer: An interruption can occur due to a hardware event like a keyboard input or a timer. The CPU pauses the current cycle, saves its state, handles the interrupt through an interrupt service routine, and then resumes normal operation.