Question:
If a semiconductor photodiode can detect a photon with a maximum wavelength of 400 nm, then its band gap energy is :
Planck's constant \(h = 6.63\times10^{-34}\) J.s. Speed of light \(c = 3\times10^{8}\) m/s
If a semiconductor photodiode can detect a photon with a maximum wavelength of 400 nm, then its band gap energy is :
Planck's constant \(h = 6.63\times10^{-34}\) J.s. Speed of light \(c = 3\times10^{8}\) m/s
Planck's constant \(h = 6.63\times10^{-34}\) J.s. Speed of light \(c = 3\times10^{8}\) m/s
Show Hint
The photodiode can detect a photon only if its energy is at least the band gap, so \(E_g = hc/\lambda_{max}\). Convert joules to eV.
Updated On: Nov 5, 2026
- 1.5 eV
- 2.0 eV
- 3.1 eV
- 1.1 eV
Show Solution
Verified By Collegedunia
The Correct Option is C
Solution and Explanation
The longest detectable wavelength corresponds to the minimum photon energy, equal to the band gap: \(E_g = \dfrac{hc}{\lambda_{max}}\).
\(E_g = \dfrac{6.63\times10^{-34}\times 3\times10^{8}}{400\times10^{-9}} = 4.97\times10^{-19}\) J.
In eV: \(E_g = \dfrac{4.97\times10^{-19}}{1.6\times10^{-19}} \approx 3.1\) eV.
Answer: (3) 3.1 eV
\(E_g = \dfrac{6.63\times10^{-34}\times 3\times10^{8}}{400\times10^{-9}} = 4.97\times10^{-19}\) J.
In eV: \(E_g = \dfrac{4.97\times10^{-19}}{1.6\times10^{-19}} \approx 3.1\) eV.
Answer: (3) 3.1 eV
Was this answer helpful?
0
0
Top JEE Main Physics Questions
- Two masses $m$ and $\frac{m}{2}$ are connected at the two ends of a massless rigid rod of length $l$. The rod is suspended by a thin wire of torsional constant $k$ at the centre of mass of the rod-mass system(see figure). Because of torsional constant $k$, the restoring torque is $\tau =k\theta$ for angular displacement $\theta$. If the rod is rota ted by $\theta_0$ and released, the tension in it when it passes through its mean position will be:
A black body is at a temperature of 2880 K. The energy of radiation emitted by this body with wavelength between 499 nm and 500 nm is U1, between 999 nm and 1000 nm is U2 and between 1499 nm and 1500 nm is U3. The Wien's constant, b = 2.88×106 nm-K. Then,
- $I _{ CM }$ is the moment of inertia of a circular disc about an axis (CM) passing through its center and perpendicular to the plane of disc $I_{A B}$ is it's moment of inertia about an axis $AB$ perpendicular to plane and parallel to axis $CM$ at a distance $\frac{2}{3} R$ from center Where $R$ is the radius of the dise The ratio of $I _{ AB }$ and $I _{ CM }$ is $x: 9$ The value of $x$ is______
- A nucleus disintegrates into two smaller parts, which have their velocities in the ratio $3: 2$ The ratio of their nuclear sizes will be $\left(\frac{x}{3}\right)^{\frac{1}{3}}$ The value of ' $x$ ' is:-
- A particle starts with an initial velocity of 10.0 m/s along x-direction and accelerates uniformly at the rate of 2.0 m/s$^2$. The time taken by the particle to reach the velocity of 60.0 m/s is
View More Questions
Top JEE Main Semiconductor electronics: materials, devices and simple circuits Questions
- Which of the following is metal compound semiconductor?
- A light emitting diode (LED) is fabricated using GaAs semiconducting material whose band gap is 1.42 eV. The wavelength of light emitted from the LED is:
- Which of the diode circuit shows correct biasing used for the measurement of dynamic resistance of p-n junction diode :
- The acceptor level of a p-type semiconductor is 6eV. The maximum wavelength of light which can create a hole would be : Given hc = 1242 eV nm.
- To measure the temperature coefficient of resistivity $\alpha$ of a semiconductor, an electrical arrangement shown in the figure is prepared. The arm BC is made up of the semiconductor. The experiment is being conducted at $25^\circ \text{C}$ and the resistance of the semiconductor arm is $3 \, \text{m}\Omega$. Arm BC is cooled at a constant rate of $2^\circ \text{C/s}$. If the galvanometer G shows no deflection after 10 s, then $\alpha$ is:
View More Questions
Top JEE Main Questions
- Two masses $m$ and $\frac{m}{2}$ are connected at the two ends of a massless rigid rod of length $l$. The rod is suspended by a thin wire of torsional constant $k$ at the centre of mass of the rod-mass system(see figure). Because of torsional constant $k$, the restoring torque is $\tau =k\theta$ for angular displacement $\theta$. If the rod is rota ted by $\theta_0$ and released, the tension in it when it passes through its mean position will be:
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)- The value of is
- The number of terms of an is even. The sum of the odd terms is and of the even terms is . The last term exceeds the first by . Then the number of terms in the series is ______.
A black body is at a temperature of 2880 K. The energy of radiation emitted by this body with wavelength between 499 nm and 500 nm is U1, between 999 nm and 1000 nm is U2 and between 1499 nm and 1500 nm is U3. The Wien's constant, b = 2.88×106 nm-K. Then,
View More Questions