# Describing Logic Circuits in Digital Logic Design MCQs

Q1. The format used to present the logic output for the various combinations of logic inputs to a gate is called a(n):.

A. truth table..

B. input logic function..

C. Boolean constant..

D. Boolean variable..

Q2. What is the basic difference between AHDL and VHDL?.

A. ADHL is used in all PLD's..

B. VHDL is used in all PLD's..

D. VHDL is proprietary..

Q3. A small circle on the output of a logic gate is used to represent the:.

A. Comparator operation..

B. OR operation..

C. NOT operation..

D. AND operation..

Q4. In VHDL, the mode of a port does not define:.

A. an input..

B. an output..

C. both an input and an output..

D. the TYPE of the bit..

Answer= the TYPE of the bit.

Q5. Which of the following equations would accurately describe a 4-input OR gate when A = 1, B = 1, C = 0, and D = 0?.

A. 1 + 1 + 0 + 0 = 1.

B. 1 + 1 + 0 + 0 = 01.

C. 1 + 1 + 0 + 0 = 0.

D. 1 + 1 + 0 + 0 = 00.

Answer= 1 + 1 + 0 + 0 = 1

Q6. How are the statements between BEGIN and END not evaluated in VHDL?.

A. Constantly.

B. Simultaneously.

C. Concurrently.

D. SeQntially.

Q7. A NOR gate with one HIGH input and one LOW input:.

A. will output a HIGH.

B. functions as an AND.

C. will not function.

D. will output a LOW.

Q8. A NAND gate has:.

A. active-LOW inputs and an active-HIGH output..

B. active-LOW inputs and an active-LOW output..

C. active-HIGH inputs and an active-HIGH output..

D. active-HIGH inputs and an active-LOW output..

Answer= active-HIGH inputs and an active-LOW output.

Q9. The logic gate that will have HIGH or "1" at its output when any one of its inputs is HIGH is a(n):.

A. NOR gate.

B. OR gate.

C. AND gate.

D. NOT operation.

Q10. An OR gate with inverted inputs functions as:.

A. an AND gate..

B. a NAND gate..

C. a NOR gate..

D. an inverter..