46. An input/output device at which data enters or leaves a computer system is

A. Keyboard
B. Terminal
C. Printer
D. Plotter
E. None of the above

47. The fastest type of memory from the following list is

A. tape
B. semiconductor memory
C. disk
D. bubble memory
E. None of the above

48. Which of the following is a secondary memory device?

A. Keyboard
B. Disk
C. ALU
D. All of the above
E. None of the above

49. The register which keeps track of the execution of a program and which contains the memory address of the instruction currently being executed is known as

A. Index register
B. Memory address register
C. Program counter
D. Instruction register
E. None of the above