Download App

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

Rajasthan BoardEnglish MediumSTD 12 SciencePhysicsSemiconductor Electronic: Material, Devices And Simple Circuits4 Marks
Question
When the diode is forward biased, it is found that beyond forward voltage $V = V_k,$ called knee voltage, the conductivity is very high. At this value of battery biasing for $p-n$ junction, the potential barrier is overcome and the current increases rapidly with increase in forward voltage.
When the diode is reverse biased, the reverse bias voltage produces a very small current about a few microamperes which almost remains constant with bias. This small current is reverse saturation current.
  1. In which of the following figures, the $p-n$ diode is forward biased.
  1.  
  1.  
  1.  
  1.  
  1. Based on the $V-I$ characteristics of the diode, we can classify diode as:
  1. $Bi-$ directional device.
  2. Ohmic device.
  3. Non $-$ ohmic device.
  4. Passive element.
  1. The $V-I$ characteristic of a diode is shown in the figure. The ratio of forward to reverse bi as resistance is:
  1. $100$
  2. $10^6$
  3. $10$
  4. $10^{-6}$
  1. In the case of forward biasing of a $p-n$ junction diode, which one of the following figures correctly depicts the direction of conventional current $($indicated by an arrow mark$)$?
  1.  
  1.  
  1.  
  1.  
  1. If an ideal junction diode is connected as shown, then the value of the current I is:
  1. $0.013A$
  2. $0.02A$
  3. $0.01A$
  4. $0.1A$
✓

Answer

  1. $(c)$

The $p-n$ diode is forward biased when $p-$ side is at a higher potential than $n-$ side.
  1. $(c)$ Non $-$ ohmic device.
  2. $(d) 10^{-6}$
Forward bias resistance,
$\text{R}_1=\frac{\triangle\text{V}}{\triangle\text{I}}=\frac{0.8-0.7}{(20-10)\times10^{-6}}$
$=\frac{0.1}{10\times10^{-3}}=10$
Reverse bias resistance, $\text{R}_2=\frac{10}{1\times10^{-6}}=10^7$
Then, the ratio of forward to reverse bias resistance,
$\frac{\text{R}_1}{\text{R}_2}=\frac{10}{10^7}=10^{-6}$​​​​​​​
  1. $(d) $

In p-region the direction of conventional current is same as flow of holes. In $n-$ region, the direction of conventional current is opposite to the flow of electrons.
  1. $(c)\  0.01A$
In the given circuit the junction diode is forward biased and offers zero resistance.
$\therefore$ The current, $\text{I}=\frac{\text{3V-1V}}{200\Omega}=\frac{\text{2V}}{200\Omega}=0.01\text{A}.$​​​​​​​

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 "4 Marks Questions" 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

A fat person is standing on a light plank floating on a calm lake. The person walks from one end to the other on the plank. His friend sitting on the shore watches him and finds that the person hardly moves any distance because the plank moves backward about the same distance as the person moves on the plank. Explain.
→
When a current/ flows through a coil, flux linked with it is $\phi=\text{LI},$ where $L$ is a constant known as self inductance of the coil. Any change in current sets up an induced $emf$ in the coil. Tims, self inductance of a coil is the induced emf set up in it when the current passing through it changes at the unit rate. It is a measure of the opposition to the growth or the decay of current flowing through the coil. Also, value of self inductance depends on the number of turns in the solenoid, its area of cross$-$section and the relative permeability of its core material.
  1. The inductance in a coil plays the same role as:
  1. Inertia in mechanics.
  2. Energy in mechanics.
  3. Momentum in mechanics.
  4. Force in mechanics.
  1. A current of $2.5A$ flows through a coil of inductance $5H.$ The magnetic flux linked with the coil is:
  1. $0.5\ Wb$
  2. $12.5\ Wb$
  3. Zero
  4. $2\ Wb$
  1. The inductance $L$ of a solenoid depends upon its radius $R$ as:
  1. $\text{L}\propto\text{R}$
  2. $\text{L}\propto\frac{1}{\text{R}}$
  3. $\text{L}\propto\text{R}^2$
  4. $\text{L}\propto\text{R}^3$
  1. The unit of self$-$inductance is:
  1. Weber ampere
  2. Weber$^{-1}$ ampere
  3. Ohm second
  4. Farad
  1. The induced $e.m.f.$ in a coil of $10$ henry inductance in which current varies from $9A$ to $4A$ in $0.2$ second is:
  1. $200V$
  2. $250V$
  3. $300V$
  4. $500V $
→
Drive the formula for the magnifying power of a compound microscope if the final images formed at Infinity. Draw the necessary diagram.
→
A police jeep is chasing a culprit going on a motorbike. The motorbike crosses a turning at a speed of $72\ km/h$. The jeep follows it at a speed of $90\ km/h,$ crossing the turning ten seconds later than the bike. Assuming that they travel at constant speeds, how far from the turning will the jeep catch up with the bike?
→
Calculate $\frac{\text{n(T)}}{\text{n}(1000\text{K})}$ for tungsten emitter at T = 300K, 2000K and 3000K, where n(T) represents the number of thermions emitted per second by the surface at temperature T. Work function of tungsten is 4.52eV.
→
Neutrons and protons are identical particle in the sense that their masses are nearly the same and the force, called nuclear force, does into distinguish them. Nuclear force is the strongest force. Stability of nucleus is determined by the neutron proton ratio or mass defect or packing fraction. Shape of nucleus is calculated by quadrupole moment and spin of nucleus depends on even or odd mass number. Volume of nucleus depends on the mass number. Whole mass of the atom $($nearly $99\%)$ is centered at the nucleus.
  1. The correct statements about the nuclear force is/ are.
  1. Change independent.
  2. Short range force.
  3. Non $-$ conservative force.
  4. All of these.
  1. The range of nuclear force is the order of.
  1. $2 \times 10^{-10}m$
  2. $1.5 \times 10^{-20}m$
  3. $1.2.\times ^10^{-4}m$
  4. $1.4 \times 10^{-15}m$
  1. A force between two protons is same as the force between proton and neutron. The nature of the force is.
  1. Electrical force.
  2. Weak nuclear force.
  3. Gravitational force.
  4. Strong nuclear force.
  1. Two protons are kept at a separation of $40 A. F_n$ is the nuclear force and $F_e$ is the electrostatic force between them. Then.
  1. $F_n<< F_e$
  2. $F_n= F_e$
  3. $F_n >> F_e$
  4. $F_n = F_e$
  1. $AD$ the nucleons in an atom are held by.
  1. Nuclear forces
  2. Van der Waal's forces
  3. Tensor forces
  4. Coulomb forces
→
Electrons oscillating in a circuit give rise to radiowaves. A transmitting antenna radiates most effectively the radiowaves of wavelength equal to the size of the antenna. The infrared waves incident on a substance set into oscillation all its electrons, atoms and molecules. This increases the internal energy and hence the temperature of the substance.

(i) If $v _{ g }, v _{ X }$ and $v _{ m }$ are the speeds of gamma rays, X -rays and microwaves respectively in vacuum, then
(a) $v_g>v_X>v_m$ (b) $v_g<v_X<v_m$ (c) $v_g>v_X>v_m$ (d) $v_g=v_X=v_m$

(ii) Which of the following will deflect in electric field?
(a) ultraviolet rays (b) $\gamma$-rays (c) X-rays (d) cathode rays

(iii) $\gamma$-rays are detected by
(a) point contact diodes (b) ionization chamber (c) thermopiles (d) photocells

OR

We consider the radiation emitted by the human body. Which one of the following statements is true?
i. The radiation emitted is in the infrared region.
ii. The radiation is emitted only during the day.
iii. The radiation is emitted during the summers and absorbed during the winters.
iv. The radiation emitted lies in the ultraviolet region and hence it is not visible.
(a) Option (iv) (b) Option (ii) (c) Option (iii) (d) Option (i)

(iv) The frequency of electromagnetic wave, which best suited to observe a particle of radius $3 \times 10^{-4} cm$ is the order of
(a) $10^{14} Hz$
(b) $10^{12} Hz$
(c) $10^{13} Hz$
(d) $10^{15} Hz$
→
A uniform magnetic field of $1.5 T$ exists in a cylindrical region of radius $10.0 \ cm,$ its direction parallel to the axis along east to west. $A$ wire carrying current of $7.0 A $ in the north to south direction passes through this region. What is the magnitude and direction of the force on the wire if,
  1. The wire intersects the axis,
  2. The wire is turned from $N-S$ to northeast $-$ northwest direction,
  3. The wire in the $N-S$ direction is lowered from the axis by a distance of $6.0 \ cm$?
→
Two long bar magnets are placed with their axes coinciding in such a way that the north pole of the first magnet is 2·0cm from the south pole of the second. If both the magnets have a pole strength of 10A-m, find the force exerted by one magnet on the other.
→
The magnetic field at a point, $10\ cm$ away from a magnetic dipole, is found to be $2.0 \times 10^{-4 }T$. find the magnetic moment of the dipole if the point is.
  1. In end-on position of the dipole.
  2. In broadside-onposition of the dipole.
→