For the given logic circuit, which of the following inputs combination will make both LED$-1$ and LED$-2$ to glow? ![JEE Main 2026 Physics, Semiconductors — question figure](https://prepforbharat.s3.ap-south-1.amazonaws.com/exam/615f0e999476412f48314daf/Physics/images/Semiconductors/69d8073481239f6567c4f2fd/question_1__q_69d8073481239f6567c4f2fd__cdn-question-pool.getmarks.app__05APRS1__q45_d1__0847c50074_final_ppt_sync.png)

JEE Main 2026 — Physics Modern Physics

2026mcqeasy

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

JEE Main 2026 Physics, Semiconductors — question figure

Official previous-year question

Held on 5 Apr 2026 · Verified 6 Jul 2026.

Options

A
$A = 0, B = 1, C = 1$
B
$A = 1, B = 0, C = 0$
C
$A = 1, B = 0, C = 1$
D
$A = 1, B = 1, C = 0$

Did you get this right?

Solution

Let the output of the OR gate be $Y_1$ .

$Y_1 = A + B$

For LED-1 to glow, $Y_1$ must be $1$ , which means $A + B = 1$ .

Let the output of the first AND gate be $Y_2$ .

$Y_2 = Y_1 \cdot C = (A + B) \cdot C$

Let the output of the second AND gate be $Y_3$ .

$Y_3 = A \cdot Y_2 = A \cdot (A + B) \cdot C$

For LED-2 to glow, $Y_3$ must be $1$ .

Simplifying the Boolean expression for $Y_3$ :

$Y_3 = (A \cdot A + A \cdot B) \cdot C$

$Y_3 = (A + AB) \cdot C$

$Y_3 = A(1 + B) \cdot C$

$Y_3 = A \cdot C$

For $Y_3 = 1$ , we require $A = 1$ and $C = 1$ .

If $A = 1$ , then $Y_1 = 1 + B = 1$ for any value of $B$ , satisfying the condition for LED-1 to glow.

From the given options, the combination $A = 1, B = 0, C = 1$ satisfies these conditions.

Answer: $A = 1, B = 0, C = 1$

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JEE Main 2026 — Physics Modern Physics

2026mcqeasy

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

JEE Main 2026 Physics, Semiconductors — question figure

Official previous-year question

Held on 5 Apr 2026 · Verified 6 Jul 2026.

Options

A
$A = 0, B = 1, C = 1$
B
$A = 1, B = 0, C = 0$
C
$A = 1, B = 0, C = 1$
D
$A = 1, B = 1, C = 0$

Did you get this right?

Solution

Let the output of the OR gate be $Y_1$ .

$Y_1 = A + B$

For LED-1 to glow, $Y_1$ must be $1$ , which means $A + B = 1$ .

Let the output of the first AND gate be $Y_2$ .

$Y_2 = Y_1 \cdot C = (A + B) \cdot C$

Let the output of the second AND gate be $Y_3$ .

$Y_3 = A \cdot Y_2 = A \cdot (A + B) \cdot C$

For LED-2 to glow, $Y_3$ must be $1$ .

Simplifying the Boolean expression for $Y_3$ :

$Y_3 = (A \cdot A + A \cdot B) \cdot C$

$Y_3 = (A + AB) \cdot C$

$Y_3 = A(1 + B) \cdot C$

$Y_3 = A \cdot C$

For $Y_3 = 1$ , we require $A = 1$ and $C = 1$ .

If $A = 1$ , then $Y_1 = 1 + B = 1$ for any value of $B$ , satisfying the condition for LED-1 to glow.

From the given options, the combination $A = 1, B = 0, C = 1$ satisfies these conditions.

Answer: $A = 1, B = 0, C = 1$

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JEE Main 2026 — Physics Modern Physics

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Solution

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JEE Main 2026 — Physics Modern Physics

Options

Did you get this right?

Solution

Your note

JEE Main Modern Physics in other years

More JEE Main Modern Physics questions

Other Physics topics for JEE Main

Mechanics

Electromagnetism

Optics

Thermodynamics

Waves & Oscillations

Keep practicing Modern Physics