Logic gates and truth tables Theory part 3
Concept ID: XI_U1_LOGIC_GATES_TRUTH_TABLES.
Primary Sub-subtopic: Logic gates and truth tables.
Question-bank grouping: Boolean Logic and Logic Circuits.
Use this lecture for theory, examples, misconceptions, and short PYQ checks mapped to this concept ID.
Key things we'll cover
Logic gates and truth tables
PYQ references used by both prompts6 included1 excluded
Flagged questions are excluded from both Study Notes and PPT references until corrected in Paper Analyzer.
Included
ID 1347 · 2025 · 1 mark(s)
Name the universal gates used in digital logic circuits and provide their logic symbols for two-variable inputs.
Boolean Logic and Logic Circuits → De Morgan's laws and logic circuits, Logic gates and truth tables
Included
ID 1612 · 2025 · 2 mark(s)
State and prove the De Morgan's law using truth table.
Boolean Logic and Logic Circuits → De Morgan's laws and logic circuits, Logic gates and truth tables
Included
ID 1213 · 2025 · 3 mark(s)
a) State DeMorgan's Law of Boolean Algebra and verify them using truth table.
b) Draw a logic circuit diagram for the Boolean expression:
X=A'BC(A+D)'
Boolean Logic and Logic Circuits → De Morgan's laws and logic circuits, Logic gates and truth tables
Excluded
ID 1283 · 2025 · 4 mark(s)
(a) Write the Boolean expression of the following logic circuit
[IMAGE]
(b) Verify X+XY=X using Truth Table.
Boolean Logic and Logic Circuits → De Morgan's laws and logic circuits, Logic gates and truth tables
Awaiting categorisation review
Included
ID 1327 · 2025 · 4 mark(s)
Riya is working on a school project that involves building a simple security alarm system using logic gates. She uses sensors at two doors and connects them to a logic circuit. The alarm should sound only when at least one door is open. She uses two inputs:
- A for Door 1 (1 = open, 0 = closed)
- B for Door 2 (1 = open, 0 = closed)
a) Which logic gate should Riya use to make the alarm sound when at least one door is open?
b) What will be the output of the circuit if both doors are closed (A=0, B=0)?
c) Which of the following input combination(s) will trigger the alarm?
I. A = 1, B = 0
II. A = 0, B = 1
III. A = 1, B = 1
IV. All of the above
d) Draw the logic gate symbol used by Riya, showing two inputs representing the doors and one output for the alarm.
Boolean Logic and Logic Circuits → De Morgan's laws and logic circuits, Logic gates and truth tables
Included
ID 1107 · 2025 · 5 mark(s)
Partigya, a student of class 11 is designing a circuit diagram. Help her to get the output out of it at different stages.
(i) What will be the output at C?
(ii) What will be the output at D?
(iii) What will be the output at E?
(iv) What will be the output at Z?
(v) A cooler should turn ON when the door is closed and the fan is ON. Which gate should be used?
Boolean Logic and Logic Circuits → De Morgan's laws and logic circuits, Logic gates and truth tables
Included
ID 1185 · 2025 · 5 mark(s)
Ms Manali is a Assistant Programmer in HCL Technologies in Gurugram. She is studing about the logical circuits and verification of various laws of Boolean Algebra. Give direction to resolve following
a. Draw logic circuit diagram for the following expression-
Y = ab + b'c + c'a'
b. State DE Morgan's Law of Boolean Algebra and verify them using truth table.
Boolean Logic and Logic Circuits → De Morgan's laws and logic circuits, Logic gates and truth tables