AQA A LEVEL COMPUTER SCIENCE 7517 2
EXAMINATION TEST 2026 QUESTIONS WITH
ANSWERS GRADED A+
◉ Control Unit. Answer: Coordinates activities in the CPU, memory and
peripherals
◉ Clock. Answer: A continuous sequence of clock pulses to step the
control unit through its operations
◉ Registers. Answer: Very fast memory stored on or near the processor
◉ Program Counter (PC). Answer: Holds the address of the next
instruction to be executed
◉ Current Instruction Register (CIR). Answer: Stores the current
instruction (in binary)
◉ Memory Address Register (MAR). Answer: Holds the address of a
memory location from which data will be read or data will be written to
, ◉ Memory Buffer Register (MBR). Answer: Temporarily stores the data
read from or written to memory
◉ Status Register (SR). Answer: Contains many bits that are set (1) or
cleared (0) depending on the result of an instruction
◉ Clock Speed. Answer: The frequency at which the system clock ticks
◉ Bus Width. Answer: The number of parallel signal lines or wires
allocated to a bus
◉ Word Length. Answer: The number of digits in a binary word
◉ Cache Memory. Answer: A small amount of very fast memory
◉ Increasing Clock Speed. Answer: Reduces the time taken to execute
instructions
◉ Increasing Word Length. Answer: Registers can store more bits and
the processor can process more bits in one go
◉ Increasing Data Bus Width. Answer: Enables more bits to be
transferred between main memory and the processor at one time
EXAMINATION TEST 2026 QUESTIONS WITH
ANSWERS GRADED A+
◉ Control Unit. Answer: Coordinates activities in the CPU, memory and
peripherals
◉ Clock. Answer: A continuous sequence of clock pulses to step the
control unit through its operations
◉ Registers. Answer: Very fast memory stored on or near the processor
◉ Program Counter (PC). Answer: Holds the address of the next
instruction to be executed
◉ Current Instruction Register (CIR). Answer: Stores the current
instruction (in binary)
◉ Memory Address Register (MAR). Answer: Holds the address of a
memory location from which data will be read or data will be written to
, ◉ Memory Buffer Register (MBR). Answer: Temporarily stores the data
read from or written to memory
◉ Status Register (SR). Answer: Contains many bits that are set (1) or
cleared (0) depending on the result of an instruction
◉ Clock Speed. Answer: The frequency at which the system clock ticks
◉ Bus Width. Answer: The number of parallel signal lines or wires
allocated to a bus
◉ Word Length. Answer: The number of digits in a binary word
◉ Cache Memory. Answer: A small amount of very fast memory
◉ Increasing Clock Speed. Answer: Reduces the time taken to execute
instructions
◉ Increasing Word Length. Answer: Registers can store more bits and
the processor can process more bits in one go
◉ Increasing Data Bus Width. Answer: Enables more bits to be
transferred between main memory and the processor at one time
