21. Which of the following is often used as an alternative to the light pen or in association with storage tube displays?

A. Digitizer
B. Trackball
C. Mouse
D. Tablet
E. None of the above

22. The general CAD system was developed by considering a wide range of possible uses of such a system.

A. Mechanical engineering design
B. Animation and graphic design
C. Structural engineering design and Electronic circuit design
D. All of the above
E. None of the above

23. Relay ladder logic is used in a PC because:

A. it is impossible to write a control program for a machine in any other logic
B. it is the best industrial control language ever developed.
C. most industrial control personnel are familiar with relay ladder logic diagrams and this is the easiest for them to use
D. All of the above
E. None of the above

24. The “end-effector” of a robot:

A. can be an actual tool
B. is the robot “hand”
C. may have a gripping action
D. All of the above
E. None of the above

25. The program execution time:

A. must be slower than the fastest mechanical operation that is to be controlled
B. will vary depending on the language used
C. cannot be changed once the program is written
D. All of the above
E. None of the above