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Saturday, 31 October

JEE Main 2021 · PhysicsMultiple choiceDiagram basedMediumDiagram reading

JEE Main 24 February 2021, Shift 2, Physics Q20

Question 20 of 90 in this shift, Physics question 20 of 30, Section A.

The logic circuit shown above is equivalent to :

The figure, in words

Stem figure (printed above the question text, on page 15): input A (open circle terminal) goes directly to the upper input of an OR-shaped gate (curved back, pointed front); input B (open circle terminal) goes through a NOT symbol (triangle with a small circle) to the lower input of the same gate; the gate output goes through a second NOT symbol (triangle with small circle) to output terminal C (open circle).
  1. (1)[figure: gate with inputs A and B; B passes through a NOT gate (triangle with small circle) into the lower input of a gate drawn with flat back and curved front and a small circle at the output, then output C]
  2. (2)[figure: gate with inputs A and B; A passes through a NOT gate into the upper input of a gate drawn with flat back and curved front and a small circle at the output, then output C]
  3. (3)[figure: gate with inputs A and B; A passes through a NOT gate into the upper input of a gate drawn with flat back and curved front and no circle at the output, then output C]Official answer
  4. (4)[figure: gate with inputs A and B drawn with curved back and pointed front (OR-shape) with a small circle at the output, then output C]

Official answer

Option 3

NTA final key.

Chapter
Semiconductor Electronics: Materials, Devices and Simple Circuits
Topic
Logic Gates
Idea tested
Combinational Logic Circuits

Same idea in other shifts

Asked 31× in all
  1. 2 Apr 2026, Shift 2 · Q30If X and Y are the inputs, the given circuit works asMediumDiagram basedHas a figure
  2. 4 Apr 2026, Shift 1 · Q38Two 44 bits binary numbers, A=1101A=1101 and B=1010B=1010 are given in the inputs of a logic circuit shown in figure below. The output (YY) will…EasyDiagram basedHas a figure
  3. 5 Apr 2026, Shift 1 · Q45For the given logic circuit, which of the following inputs combination will make both LED-1 and LED-2 to glow?EasyDiagram basedHas a figure
  4. 6 Apr 2026, Shift 2 · Q43Refer to the logic circuit given below. For two inputs (A=1A=1, B=1B=1) and (A=0A=0, B=1B=1), output (YY) will be __________.EasyDiagram basedHas a figure
  5. 2 Apr 2025, Shift 2 · Q39In the digital circuit shown in the figure, for the given inputs the P and Q values are :MediumDiagram basedHas a figure
  6. 3 Apr 2025, Shift 1 · Q45Choose the correct logic circuit for the given truth table having inputs A and B. Inputs A, B / Output Y: A=0,B=0: Y=0 A=0,B=1: Y=0…MediumDiagram basedHas a figure
  7. 3 Apr 2025, Shift 2 · Q45The truth table corresponding to the circuit given below is :EasyDiagram basedHas a figure
  8. 7 Apr 2025, Shift 2 · Q45Consider the following logic circuit. The output is Y=0Y=0 when :EasyDiagram 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.