Download App

Semiconductor Electronic: Material, Devices And Simple Circuits — Physics STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 SciencePhysicsSemiconductor Electronic: Material, Devices And Simple Circuits3 Marks
Question
  1. Describe the working principle of a solar cell. Mention three basic processes involved in the generation of emf.
  2. Why are Si and GaAs preferred materials for solar cells?
✓

Answer

  1. When solar cell is illuminated with light photons of energy $(hv)$ greater than the energy gap $\text{E}_{\text{g}}$ of the semiconductor, then electron hole pairs are generated due to absorption of photons.
The three basic processes involved in the generation of emf:
  1. Generation of e-h pairs due to light with close to the junction.
  2. Separation of electrons and holes due to electric field of the depletion region.
  3. The electrons reaching the n side are collected by the front contact and holes reaching p side are collected by back contact.
  1. Solar radiation has maximum intensity of photons of energy = 1.5eV.
Hence semiconducting materials Si and GaAs, with band gap $\approx$ 1.5 eV, are preferred materials for solar cells.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "3 Marks Question" from Semiconductor Electronic: Material, Devices And Simple Circuits→Semiconductor Electronic: Material, Devices And Simple Circuits — all question types→Physics STD 12 Science question papers→Rajasthan Board STD 12 Science question papers→Rajasthan Board question paper generator→

Similar questions

An electric dipole with dipole moment $4 \times 10^{-9} Cm$ is aligned at $30^\circ $ with the direction of a uniform electric field of magnitude $5 \times 10^4 NC^{-1}.$ Calculate the magnitude of the torque acting on the dipole.
→
Give reasons for the following:
  1. The Zener diode is fabricated by heavily doping both the p and n sides of the junction.
  2. A photodiode, when used as a detector of optical signals is operated under reverse bias.
  3. The band gap of the semiconductor used for fabrication of visible LED’s must at least be 1.8eV.
→
A source emits light of wavelengths $555\ nm$ and $600\ nm$. The radiant flux of the $555\ nm$ part is $40W$ and of the $600\ nm$ part is $30W$. The relative luminosity at $600\ nm$ is $0\ '6$. Find:
  1. The total radiant flux.
  2. The total luminous flux.
  3. The luminous efficiency.
→
The equation for the vibration of a string, fixed at both ends vibrating in its third harmonic, is given by$\text{y}=(0.4\text{cm})\sin\big[(0.314\text{cm}^{-1})\text{x}\big]\cos\big[(600\pi\text{s}^{-1})\text{t}\big]$
  1. What is the frequency of vibration?
  2. What are the positions of the nodes?
  3. What is the length of the string?
  4. What is the wavelength and the speed of two travelling waves that can interfere to give this vibration ?
→
A change of 0.2mA in the base current causes a change of 5mA in the collector current for a common emitter amplifier.
  1. Find the ac current gain of the transistor.
  2. If the input resistance is $2\text{k}\Omega$ and its voltage gain is 75, calculate the load resistor used in the circuit.
→
Sketch a graph between frequency of incident radiations and stopping potential for a given photosensitive material. What information can be obtained from the value of the intercept on the potential axis? A source of light of frequency greater than the threshold frequency is placed at a distance of 1 m from the cathode of a photo-cell. The stopping potential is found to be V. If the distance of the light source from the cathode is reduced, explain giving reasons, what change will you observe in the.
  1. photoelectric current,
  2. stopping potential.
→
A convex lens of focal length 20 cm is placed coaxially with a convex mirror of radius of curvature 20 cm. The two are kept at 15 cm from each other. A point object lies 60 cm in front of the convex lens. Draw a ray diagram to show the formation of the image by the combination. Determine the nature and position of the image formed.
→
Mass of a particle depends on its speed. Does the attraction of the earth on the particle also depend on the particle's speed?
→
A laser beam has intensity $2.5 \times 10^{14}\ Wm^{-2}.$ Find amplitudes of electric and magnetic fields in the beam.
→
Solve the previous problem if the paperweight is inverted at its place so that the spherical surface touches the paper.
→