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Saturday, 31 October

JEE Main 2021 · PhysicsMultiple choiceDiagram basedMediumData or graph

JEE Main 26 February 2021, Shift 2, Physics Q4

Question 4 of 90 in this shift, Physics question 4 of 30, Section A.

Draw the output signal Y in the given combination of gates.

The figure, in words

Left: two signal-vs-t(s) graphs, time axis marked 0 to 5. A: high from 0 to 2, low from 2 to 3, high from 3 to 5. B: low from 0 to 1, high from 1 to 2, low from 2 to 3, high from 3 to 4, low from 4 to 5. Right: gate circuit with A entering a NAND gate drawn with a small box on its input side (the box joins the input line to the gate), B entering a second input line; the NAND output and B go into an OR gate; OR output goes into a NOT gate (triangle with bubble) whose output is labelled Y.
  1. (1)[figure: signal graph vs t(s); high level from t = 1 to t = 4, zero elsewhere]
  2. (2)[figure: signal graph vs t(s); high level from t = 0 to t = 1, zero from 1 to 4, high again from t = 4 onward to about 5]Official answer
  3. (3)[figure: signal graph vs t(s); zero throughout, no high level drawn]
  4. (4)[figure: signal graph vs t(s); high level constant from t = 0 to t = 5]

Official answer

Option 2

NTA final key.

Chapter
Semiconductor Electronics: Materials, Devices and Simple Circuits
Topic
Logic Gates
Idea tested
Timing Diagrams and Waveform Analysis

Same idea in other shifts

Asked 7× in all
  1. 8 Apr 2026, Shift 2 · Q45The output YY for the given inputs AA and BB to the circuit is :MediumDiagram basedHas a figure
  2. 8 Apr 2023, Shift 1 · Q42For the logic circuit shown, the output waveform at Y is:MediumDiagram basedHas a figure
  3. 13 Apr 2023, Shift 1 · Q47For the following circuit and given inputs A and B, choose the correct option for output 'Y'HardDiagram basedHas a figure
  4. 27 Jul 2022, Shift 1 · Q49A logic gate circuit has two inputs A and B and output Y. The voltage waveforms of A, B and Y are shown below. The logic gate circuit is:EasyDiagram basedHas a figure
  5. 27 Jun 2022, Shift 1 · Q49Identify the correct Logic Gate for the following output (Y) of two inputs A and B.MediumDiagram basedHas a figure
  6. 3 Aug 2021, Shift 1 · Q20In the given figure, a logic circuit has the input waveforms `A' and `B'. The correct output waveform will be -MediumDiagram basedHas a figure

Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. This question needs a figure we do not reproduce; it is described in words above. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.