Semiconductors & Communication · JEE Main previous year questions

2023 37 questions

1. Q452023 · 29 Jan 2023 · Shift 2
   
   1. A.
   2. B.
   3. C.
   4. D.
   Show answer

   Answer: D

2. Q502023 · 29 Jan 2023 · Shift 2

   The modulation index for an A.M. wave having maximum and minimum peak-to-peak voltages of 14 mV and 6 mV respectively is-

   1. A.0.4
   2. B.0.6
   3. C.1.4
   4. D.0.2
   Show answer

   Answer: A

3. Q342023 · 25 Jan 2023 · Shift 1

   Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R Assertion A : Photodiodes are used in forward bias usually for measuring the light intensity. Reason R : For a p-n junction diode, at applied voltage V the current in the forward bias is more than the current in the reverse bias for $|{\mathrm{V}}_{\mathrm{z}}|>\pm \mathrm{V}\ge |{\mathrm{V}}_0|$ where ${\mathrm{V}}_0$ is the threshold voltage and ${\mathrm{V}}_{\mathrm{z}}$ is the breakdown voltage. In the light of the above statements, choose the correct answer from the options given below

   1. A.Both A and R are true but R is NOT the correct explanation of A
   2. B.A is true but R is false
   3. C.Both A and R are true and R is the correct explanation of A
   4. D.A is false but R is true
   Show answer

   Answer: D

4. Q492023 · 25 Jan 2023 · Shift 1

   A message signal of frequency 5 kHz is used to modulate a carrier signal of frequency 2 MHz. The bandwidth for amplitude modulation is :

   1. A.10 kHz
   2. B.2.5 kHz
   3. C.20 kHz
   4. D.5 kHz
   Show answer

   Answer: A

5. Q502023 · 25 Jan 2023 · Shift 1

   A bowl filled with very hot soup cools from $98^{\circ }\mathrm{C}$ to $86^{\circ }\mathrm{C}$ in 2 minutes when the room temperature is $22^{\circ }\mathrm{C}$. How long it will take to cool from $75^{\circ }\mathrm{C}$ to $69^{\circ }\mathrm{C}$?

   1. A.2 minutes
   2. B.0.5 minute
   3. C.1.4 minutes
   4. D.1 minute
   Show answer

   Answer: C

6. Q332023 · 25 Jan 2023 · Shift 2

   The distance travelled by a particle is related to time t as $x=4{\mathrm{t}}^2$. The velocity of the particle at t=5s is :-

   1. A.$25\mathrm{m}{\mathrm{s}}^{-1}$
   2. B.$20\mathrm{m}{\mathrm{s}}^{-1}$
   3. C.$8\mathrm{m}{\mathrm{s}}^{-1}$
   4. D.$40\mathrm{m}{\mathrm{s}}^{-1}$
   Show answer

   Answer: D

7. Q442023 · 25 Jan 2023 · Shift 2

   Statement I : When a Si sample is doped with Boron, it becomes P type and when doped by Arsenic it becomes N-type semi conductor such that P-type has excess holes and N-type has excess electrons. Statement II : When such P-type and N-type semi-conductors, are fused to make a junction, a current will automatically flow which can be detected with an externally connected ammeter. In the light of above statements, choose the most appropriate answer from the options given below

   1. A.Statement I is incorrect but statement II is correct
   2. B.Both Statement I and statement II are correct
   3. C.Statement I is correct but statement II is incorrect
   4. D.Both Statement I and Statement II are incorrect
   Show answer

   Answer: C

8. Q582023 · 25 Jan 2023 · Shift 2· Numerical answer

   A spherical drop of liquid splits into 1000 identical spherical drops. If ${\mathrm{u}}_{\mathrm{i}}$ is the surface energy of the original drop and ${\mathrm{u}}_{\mathrm{f}}$ is the total surface energy of the resulting drops, then (ignoring evaporation), $\frac{u_f}{u_i}=\left(\frac{10}{x}\right)$. Then value of x is ____ :

   Show answer

   Answer: 1

9. Q312023 · 24 Jan 2023 · Shift 1

   Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R Assertion A : Photodiodes are preferably operated in reverse bias condition for light intensity measurement. Reason R : The current in the forward bias is more than the current in the reverse bias for a $p-n$ junction diode. In the light of the above statements, choose the correct answer from the options given below :

   1. A.Both A and R are true and R is the correct explanation of A
   2. B.A is false but R is true
   3. C.A is true but R is false
   4. D.Both A and R are true but R is NOT the correct explanation of A
   Show answer

   Answer: D

10. Q372023 · 24 Jan 2023 · Shift 1

    Two long straight wires P and Q carrying equal current 10A each were kept parallel to each other at $5\mathrm{cm}$ distance. Magnitude of magnetic force experienced by $10\mathrm{cm}$ length of wire P is ${\mathrm{F}}_1$. If distance between wires is halved and currents on them are doubled, force ${\mathrm{F}}_2$ on $10\mathrm{cm}$ length of wire P will be:

    1. A.$\frac{{\mathrm{F}}_1}{8}$
    2. B.$10{\mathrm{F}}_1$
    3. C.$\frac{{\mathrm{F}}_1}{10}$
    4. D.$8{\mathrm{F}}_1$
    Show answer

    Answer: D

11. Q492023 · 24 Jan 2023 · Shift 1
    
    1. A.$\frac{1}{3}$
    2. B.$1$
    3. C.$\frac{1}{4}$
    4. D.$\frac{1}{2}$
    Show answer

    Answer: D

12. Q312023 · 24 Jan 2023 · Shift 2
    
    1. A.NOR
    2. B.OR
    3. C.NAND
    4. D.AND
    Show answer

    Answer: C