PN Junction and Diode PYQs: JEE Mains Physics

Showing 1–42 of 42 questions

1. 1. Consider a circuit consisting of a capacitor (\(20\ \mu\)F), resistor (\(100\ \Omega\)) and two identical diodes as shown in figure. The resistance of diode under forward biasing condition is \(10\ \Omega\). The time constant of the circuit is \(\alpha \times 10^{-3}\) s. The value of \(\alpha\) is _____
   2026 Medium
2. 2. Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R
   
   Assertion A: A diode under reverse-biased condition provides very small current which is nearly independent of voltage until a critical limit at which the current increases drastically.
   
   Reason R: Below the critical voltage limit, only majority charge carriers flow which increases drastically above critical voltage.
   
   Choose the correct answer from the options given below 2026 Medium
3. 3. In a semiconductor p-n diode, the doping concentrations on p-side and n-side are \(10^{15}\text{ atoms/cm}^3\) and \(10^{18}\text{ atoms/cm}^3\), respectively. Which one of the following statements is true ? 2026 Medium
4. 4. Refer to the circuit diagram given in the figure. which of the following observations are correct?
   A. Total resistance of circuit is \(6 \Omega\)
   B. Current in Ammeter is 1 A
   C. Potential across \(A B\) is 4 Volts.
   D. Potential across CD is 4 Volts
   E. Total resistance of the circuit is \(8 \Omega\).
   
   Choose the correct answer from the options given below:
   2025 Medium
5. 5. The output voltage in the following circuit is : (Consider ideal diode case)
   2025 Medium
6. 6. What is the current through the battery in the circuit shown below?
   2025 Easy
7. 7. Which of the following circuits represents a forward biased diode?
   
   
   Choose the correct answer from the options given below : 2025 Easy
8. 8. In the given circuit, the voltage across load resistance \(\left(R_L\right)\) is _______.
   2024 Hard
9. 9. The value of net resistance of the network as shown in the given figure is _______.
   2024 Hard
10. 10. Given below are two statements : one is labeled as Assertion \(A\) and the other is labeled 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 \(\left|V_z\right| > \pm V \geq\left|V_0\right|\) where \(V_0\) is the threshold voltage and \(V _{ z }\) is the breakdown voltage. In the light of the above statements, choose the correct answer from the options given below 2023 Medium
11. 11. 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 statement, choose the correct answer from the options given below : 2023 Medium
12. 12. Given below are two statements: one is labelled as Assertion \(A\) and the other is labelled as Reason \(R\) Assertion \(A:\) Diffusion current in a \(p-n\) junction is greater than the drift current in magnitude if the junction is forward biased. Reason \(R:\) Diffusion current in a \(p-n\) junction is from the \(n\)-side to the \(p\)-side if the junction is forward biased. In the light of the above statements, choose the most appropriate answer from the options given below 2023 Medium
13. 13. If each diode has a forward bias resistance of \(25\,\Omega\) in the below circuit,Which of the following options is correct:
    2023 Medium
14. 14. In the given circuit, the current \((I)\) through the battery will be \(..........\,A\)
    2023 Medium
15. 15. 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. 2023 Medium
16. 16. A potential barrier of \(0.4 \,V\) exists across a p-n junction. An electron enters the junction from the \(n\)-side with a speed of \(6.0 \times 10^{5} \,ms ^{-1}\). The speed with which electron enters the \(p\) side will be \(\frac{x}{3} \times 10^{5} \,ms ^{-1}\) the value of \(x\) is .............. (Given mass of electron \(=9 \times 10^{-31} \,kg\), charge on electron \(=1.6 \times 10^{-19} \,C\).) 2022 Hard
17. 17. As per the given circuit, the value of current through the battery will be \(\dots \; A\).
    2022 Medium
18. 18. For using a multimeter to identify diode from electrical components. choose the correct statement out of the following about the diode 2022 Medium
19. 19. If the potential barrier across a \(p - n\) junction is \(0.6\,V\). Then the electric field intensity, in the depletion region having the width of \(6 \times 10^{-6} m\), will be \(......\times 10^{5} N / C\). 2022 Easy
20. 20. The cut-off voltage of the diodes (shown in figure) in forward bias is \(0.6 \,V\). The current through the resister of \(40 \,\Omega\) is ........... \(mA\).
    2022 Medium
21. 21. The \(I-V\) characteristics of a \(p - n\) junction diode in forward bias is shown in the figure. The ratio of dynamic resistance, corresponding to forward bias voltages of \(2 \; V\) and \(4 \; V\) respectively, is
    2022 Medium
22. 22. Two ideal diodes are connected in the network as shown in figure. The equivalent resistance between \(A\) and \(B\) is \(.......\Omega\).
    2022 Medium
23. 23. A \(5 \,V\) battery is connected across the points \(X\) and \(Y\). Assume \(D_{1}\) and \(D_{2}\) to be normal silicon diodes. Find the current (in \(A\)) supplied by the battery if the \(+ve\) terminal of the battery is connected to point \(X\)
    2021 Medium
24. 24. Consider a situation in which reverse biased current of a particular \(P-N\) junction increases when it is exposed to a light of wavelength \(\le 621\, {nm}\). During this process, enhancement in carrier concentration takes place due to generation of hole-electron pairs. The value of band gap is nearly. (In \({eV}\)) 2021 Medium
25. 25. For the forward biased diode characteristics shown in the figure, the dynamic resistance at \({I}_{{D}}=3 \,{mA}\) will be \(.....\,\Omega\)
    2021 Medium
26. 26. In the given figure, each diode has a forward bias resistance of \(30\, \Omega\) and infinite resistance in reverse bias. The current \({I}_{1}\) will be \(....\,A\)
    2021 Hard
27. 27. Match List \(I\) with List \(II.\)

    List \(I\)	List \(II\)
    \((a)\) Rectifier	\((i)\) Used either for stepping up or stepping down the \(a.c.\) voltage
    \((b)\) Stabilizer	\((ii)\) Used to convert \(a.c.\) voltage into \(d.c.\) voltage
    \((c)\) Transformer	\((iii)\) Used to remove any ripple in the rectified output voltage
    \((d)\) Filter	\((iv)\) Used for constant output voltage even when the input voltage or load current change

    Choose the correct answer from the options given below: 2021 Medium
28. 28. The circuit contains two diodes each with a forward resistance of \(50\, \Omega\) and with infinite reverse resistance. If the battery voltage is \(6\, V\), the current through the \(120\, \Omega\) resistance is \(mA\)
    2021 Hard
29. 29. Zener breakdown occurs in a \(p-n\) junction having \(p\) and \(n\) both : 2021 Medium
30. 30. Both the diodes used in the circuit shown are assumed to be ideal and have negligible resistance when these are forward biased. Built in potential in each diode is \(0.7\; \mathrm{V} .\) For the input voltages shown in the figure, the voltage (in \(Volts\)) at point \(A\) is
    2020 Medium
31. 31. In the figure, potential difference between \(A\) and \(B\) is......\(V\)
    2020 Medium
32. 32. The current \(i\) in the network is.....\(A\)
    2020 Medium
33. 33. Two identical capacitors \(\mathrm{A}\) and \(\mathrm{B}\), charged to the same potential \(5\; \mathrm{V}\) are connected in two different circuits as shown below at time \(\mathrm{t}=0\) If the charge on capacitors \(A\) and \(B\) at time \(\mathrm{t}=\mathrm{CR}\) is \(\mathrm{Q}_{\mathrm{A}}\) and \(\mathrm{Q}_{\mathrm{B}}\) respectively, then (Here \(e\) is the base of natural logarithm)
    2020 Medium
34. 34. When a diode is forward biased, it has a voltage drop of \(0.5\, V.\) The safe limit of current through the diode is \(10\, mA\). If a battery of emf \(1.5\, V\) is used in the circuit, the value of minimum resistance to be connected in series with the diode so that the current does not exceed the safe limit is\(.....\Omega\) 2020 Medium
35. 35. Ge and Si diodes conduct at \(0.3 \,V\) and \(0.7\, V\) respectively. In the following figure if Ge diode connection are reversed, the valve of \(V0\) changes by.....\(V\)
    2019 Hard
36. 36. The circuit shown below contains two ideal diodes, each with a forward resistance of \(50\,\Omega \). If the battery voltage is \(6\,V\), the current through the \(100\,\Omega \) resistance (in Amperes) is
    2019 Medium
37. 37. The reading of the ammeter for a silicon diode in the given circuit is.......\(mA\)
    2018 Medium
38. 38. The \(V-I\) characteristic of a diode is shown in the figure. The ratio of forward to reverse bias resistance is
    2017 Hard
39. 39. A \(2\,V\) battery is connected across \(AB\) as shown in the figure. The value of the current supplied by the battery when in one case battery's positive terminal is connected to \(A\) and in other case when positive terminal of battery is connected to \(B\) will respectively be
    2015 Medium
40. 40. In an unbiased \(n-p\) junction electrons diffuse from \(n-\) region to \(p-\) region because 2015 Easy
41. 41. The current voltage relation of a diode is given by \(I=(e^{1000V/T} -1)mA\) where the applied voltage \(V\) is in volts and the temperature \(T\) is in degree kelvin. If a student makes an error measuring \(±0.01\ V\) while measuring the current of \(5\ mA\) at \(300\ K\), what will be the error in the value of current in \(mA?\) 2014 Medium
42. 42. Figure shows a circuit in which three identical diodes are used . Each diode has forward resistance of \(20\,\Omega \) and infinite backward resistance. Resistors \(R_1 = R_2 = R_3 = 50\,\Omega.\) Battery voltage is \(6\,V.\) The current through \(R_3\) is.....\(mA\)
    2013 Medium

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