JEE Main Semiconductor PYQ

1. (JEE Main 2024 (Online) 6th April Evening Shift )

The acceptor level of a p-type semiconductor is $6 eV$ . The maximum wavelength of light which can create a hole would be : Given $hc = 1242 eV nm$ .

A.470 nm

B.103.5 nm

C.414 nm

D.207 nm

Correct option is (d)

The energy required to create a hole in a p-type semiconductor can be directly related to the acceptor level because this energy level represents the minimum energy required to excite an electron from the valence band into the acceptor level, effectively creating a hole. The acceptor level is given as $6 eV$ .

To find the maximum wavelength of light that can excite an electron into this level, we use the equation that relates the energy ( $E$ ) of a photon to its wavelength ( $λ$ ):

$E = \frac{h c}{λ}$

Where:

$E$ is the energy in electronvolts (eV),
$h$ is Planck's constant,
$c$ is the speed of light, and
$λ$ is the wavelength in nanometers (nm).

The product of $h c$ is given as $1242 eV nm$ , allowing us to solve for $λ$ directly:

$λ = \frac{h c}{E}$

Substituting the given values:

$λ = \frac{1242 eV nm}{6 eV} = 207 nm$

Thus, the maximum wavelength of light that can create a hole in the semiconductor by exciting an electron into the acceptor level is $207 nm$ . Therefore, the correct answer is Option D: 207 nm.

2. (JEE Main 2023 (Online) 6th April Morning Shift)

The resistivity $(ρ)$ of semiconductor varies with temperature. Which of the following curve represents the correct behaviour

A.

JEE Main 2023 (Online) 6th April Morning Shift Physics - Semiconductor Question 2 English Option 1

B.

JEE Main 2023 (Online) 6th April Morning Shift Physics - Semiconductor Question 2 English Option 2

C.

JEE Main 2023 (Online) 6th April Morning Shift Physics - Semiconductor Question 2 English Option 3

D.

JEE Main 2023 (Online) 6th April Morning Shift Physics - Semiconductor Question 2 English Option 4

The Correct Answer is Option (D)

Currently no explanation available

3. (JEE Main 2023 (Online) 1st February Evening Shift)

Choose the correct statement about Zener diode :

A. It works as a voltage regulator in reverse bias and behaves like simple pn junction diode in forward bias.

B. It works as a voltage regulator in both forward and reverse bias.

C. It works as a voltage regulator only in forward bias.

D. It works as a voltage regulator in forward bias and behaves like simple pn junction diode in reverse bias.

The Correct Answer is Option (A)

Option A is the correct statement about Zener diode. It works as a voltage regulator in reverse bias and behaves like a simple pn junction diode in forward bias. When a Zener diode is reverse-biased, it operates in the breakdown region, where a relatively constant voltage is maintained across the diode, regardless of the current flowing through it. This property makes it useful as a voltage regulator. In forward bias, the voltage applied across the diode is in the same direction as the normal direction of current flow. In this condition, the Zener diode behaves like a simple pn junction diode and allows current to flow in the forward direction.

4. (JEE Main 2023 (Online) 31st January Morning Shift)

The effect of increase in temperature on the number of electrons in conduction band ( $n_{e}$ ) and resistance of a semiconductor will be as:

A. $n_{e}$ decreases, resistance increases

B. Both $n_{e}$ and resistance increase

C. $n_{e}$ increases, resistance decreases

D. Both $n_{e}$ and resistance decrease

The Correct Answer is Option (C)

As temperature increases $n_{e}$ increases, this results in increase in conductance.

$∴ T$ increases, $n_{e}$ increases and $R$ decreases.

5. (JEE Main 2023 (Online) 25th January Evening Shift)

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 ameter.

In the light of above statements, choose the most appropriate answer from the options given below

A. Statement I is incorrect but statement II is correct

B. Both Statement I and statement II are correct

C. Statement I is correct but statement II is incorrect

D. Both Statement I and Statement II are incorrect

The Correct Answer is Option (C)

Statement I is correct but in statement II we cannot detect the current through ammeter thus the statement II is incorrect.

Semiconductor Electronics