Logic gates - OR, AND, NOT, NAND and NOR — practice questions

Question 1 · difficulty L1 · recall

An AND gate outputs 1 when

• A. any one input is 1
• B. all inputs are 0
• C. all inputs are 1
• D. exactly one input is 0

Question 2 · difficulty L1 · understanding

An OR gate outputs 1 when

• A. all inputs are 1 only
• B. all inputs are 0
• C. exactly two inputs are 0
• D. at least one input is 1

Question 3 · difficulty L2 · understanding

A NOT gate

• A. inverts its single input
• B. adds two inputs
• C. outputs 1 for every input
• D. requires two equal inputs

Question 4 · difficulty L2 · application

A NAND gate is an AND gate followed by

• A. OR
• B. NOT
• C. another AND with no inversion
• D. a resistor only

Question 5 · difficulty L2 · understanding

Refer to the logic circuit given below. For two inputs ( $A=1, B=1$ ) and ( $A=0, B=1$ ), output ( Y ) will be $\_\_\_\_$ .

• A. 1, 0 respectively
• B. 0, 1 respectively
• C. 0, 0 respectively
• D. 1, 1 respectively

Question 6 · difficulty L2 · understanding

For the given logic circuit, which of the following inputs combination will make both LED-1 and LED-2 to glow?

• A. $$\mathrm{A}=0, \mathrm{~B}=1, \mathrm{C}=1$$
• B. $$\mathrm{A}=1, \mathrm{~B}=0, \mathrm{C}=0$$
• C. $$\mathrm{A}=1, \mathrm{~B}=0, \mathrm{C}=1$$
• D. $$\mathrm{A}=1, \mathrm{~B}=1, \mathrm{C}=0$$

Question 7 · difficulty L2 · understanding

Two 4 bits binary numbers, $A=1101$ and $B=1010$ are given in the inputs of a logic circuit shown in figure below. The output $(Y)$ will be :

• A. $$Y=1101$$
• B. $$Y=0010$$
• C. $$Y=0111$$
• D. $$Y=1000$$

Question 8 · difficulty L2 · understanding

Two p-n junction diodes $D_1$ and $D_2$ are connected as shown in figure. $A$ and $B$ are input signals and $C$ is the output. The given circuit will function as a ________.

• A. AND Gate
• B. OR Gate
• C. NOR Gate
• D. NAND Gate

Question 9 · difficulty L2 · understanding

$$\text { Identify the correct truth table of the given logic circuit. }$$

• A. $$\begin{array}{|c|c|c|} \hline \text { A } & \text { B } & \text { Y } \\ \hline \hline 0 & 0 & 0 \\ \hline \hline 0 & 1 & 0 \\ \hline 1 & 0 & 1 \\ \hline 1 & 1 & 0 \\ \hline \end{array}$$
• B. $$\begin{array}{|c|c|c|} \hline \text { A } & \text { B } & \text { Y } \\ \hline \hline 0 & 0 & 0 \\ \hline \hline 0 & 1 & 1 \\ \hline 1 & 0 & 1 \\ \hline 1 & 1 & 0 \\ \hline \end{array}$$
• C. $$\begin{array}{|c|c|c|} \hline \text { A } & \text { B } & \text { Y } \\ \hline \hline 0 & 0 & 1 \\ \hline \hline 0 & 1 & 1 \\ \hline \hline 1 & 0 & 1 \\ \hline \hline 1 & 1 & 0 \\ \hline \end{array}$$
• D. $$\begin{array}{|c|c|c|} \hline \text { A } & \text { B } & \text { Y } \\ \hline \hline 0 & 0 & 1 \\ \hline \hline 0 & 1 & 0 \\ \hline 1 & 0 & 1 \\ \hline 1 & 1 & 0 \\ \hline \end{array}$$

Question 10 · difficulty L2 · understanding

$$\text { For the given logic gate circuit, which of the following is the correct truth table? }$$

• A. $$\begin{array}{c|c|c} n & m & z \\ \hline 0 & 0 & 1 \\ 0 & 1 & 1 \\ 1 & 1 & 0 \\ 1 & 0 & 0 \end{array}$$
• B. $$\begin{array}{c|c|c} n & m & z \\ \hline 0 & 0 & 1 \\ 0 & 1 & 0 \\ 1 & 1 & 1 \\ 1 & 0 & 0 \end{array}$$
• C. $$\begin{array}{c|c|c} n & m & z \\ \hline 0 & 0 & 0 \\ 0 & 1 & 1 \\ 1 & 1 & 0 \\ 1 & 0 & 1 \end{array}$$
• D. $$\begin{array}{c|c|c} n & m & z \\ \hline 0 & 0 & 1 \\ 0 & 1 & 0 \\ 1 & 1 & 0 \\ 1 & 0 & 0 \end{array}$$