Question 2 :
The depletion layer in the pn junction region is caused by
Question 3 :
Electronic configuration of germanium is {tex} 2,8,18 {/tex} and {tex} 4 . {/tex} To make it an extrinsic semiconductor, a small quantity of antimony is added.
Question 4 :
A transistor is operated in common emitter configuration at {tex} \mathrm{V _ { c }} = 2 \mathrm { V } {/tex} such that a change in base current from {tex} 100 \mu \mathrm { A } {/tex} to {tex} 200 \mu \mathrm { A } {/tex} produces a change in the collector current from {tex} 5 \mathrm { mA } {/tex} to {tex} 10 \mathrm { mA } {/tex}. The current gain is
Question 5 :
A diode having a potential difference of {tex} 0.5 \mathrm { V } {/tex} across its junction, which does not depend on current, is connected in series with a resistance of {tex} 20 \Omega {/tex} across a source. If {tex} 0.1 \mathrm { A } {/tex} passes through the resistance, then the voltage of the source is
Question 6 :
While the collector to emitter voltage is constant in a transistor, the collector current changes by {tex} 8.2 \mathrm { mA } {/tex} when the emitter current changes by {tex} 8.3 \mathrm { mA } {/tex}. The value of current gain {tex} \beta {/tex} is
Question 7 :
A light emitting diode (LED) has a voltage drop of {tex}\mathrm{2 volt}{/tex} across it and passes a current of {tex} 10 \mathrm { mA } {/tex} when it operates with a {tex}\mathrm{6 volt}{/tex} battery through a limiting resistor {tex} \mathrm R . {/tex} The value of {tex} \mathrm R {/tex} is
Question 8 :
In a transistor, a change of {tex} 8.0 \mathrm { mA } {/tex} in the emitter current produces a change of {tex} 7.9 \mathrm { mA } {/tex} in the collector current. The base current changes by
Question 10 :
When a {tex} p - n {/tex} diode is reverse biased, then
Question 11 :
In a pn junction, the barrier potential offers opposition to only
Question 12 : Which logic gate is represented by the following combination of logic gates?<br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/NEET/5dedf9a82cbd216b6cb2b140">
Question 14 :
On increasing the reverse bias to a large value in a pn junction diode, the current
Question 15 :
A transistor oscillator using a resonant circuit with an inductor {tex} L {/tex} (of negligible resistance) and a capacitor {tex} C {/tex} in series produces oscillations of frequency {tex} f . {/tex} If {tex} L {/tex} is doubled and {tex} C {/tex} is changed to {tex} 4 C , {/tex} the frequency will be
Question 16 :
A common emitter amplifier has a voltage gain of {tex} 50 , {/tex} an input impedance of {tex} 100 \Omega {/tex} and an output impedance of {tex} 200 \Omega {/tex}. The power gain of the amplifier is
Question 17 : Two identical pn junctions may be connected in series with a battery in three ways as shown :<br><img style='object-fit:contain' src="https://data-screenshots.sgp1.digitaloceanspaces.com/5dedf694750d06770ee01bd2.jpg" /><br>The potential drops across the two pn junctions are equal in
Question 18 : A {tex}2 \mathrm V{/tex} battery is connected across the points {tex} \mathrm { A } {/tex} and {tex} \mathrm { B } {/tex} as shown in the figure given below. Assuming that the resistance of each diode is zero in forward bias and inifinity in reverse bias, the current supplied by the battery when its positive terminal is connected to {tex} \mathrm { A } {/tex} is<br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/NEET/5dedf9762cbd216b6cb2b0f9"><br>
Question 19 :
The transfer ratio {tex} \beta {/tex} of a transistor is {tex} 50 . {/tex} The input resistance of the transistor when used in the common-emitter configuration is {tex} 1 \mathrm { k } \Omega {/tex}. The peak value of the collector ac current for an ac input voltage of {tex} 0.01 \mathrm { V } {/tex} peak is
Question 20 : In the circuit shown below the transistor used has a current gain {tex} \beta = 100 . {/tex} What should be the bias resistor {tex} R _ { \mathrm { B } } {/tex} so that {tex} \left. V _ { \mathrm { CE } } = 5 \mathrm { V } ? \text { (neglect } V _ { \mathrm { BE } } \right) {/tex}<br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/NEET/5dedf88f2cbd216b6cb2aff5"><br>
Question 21 :
The input resistance of a common emitter amplifier, if the output resistance {tex} 500 \mathrm { k } \Omega , {/tex} the current gain {tex} \alpha = 0.98 {/tex} and power gain is {tex} 6.0625 \times 10 ^ { 6 } , {/tex} is<br>
Question 22 :
A working transistor with three legs marked {tex} P , Q {/tex} and {tex} R {/tex} is tested using a multimeter. No conduction is found between {tex} P {/tex} and {tex} Q {/tex}. By connecting the common (negative) terminal of the multimeter to {tex} R {/tex} and the other (positive) terminal to {tex} P {/tex} or {tex} Q {/tex}, some resistance is seen on the multimeter. Which of the following is true for the transistior?
Question 24 : The figure shows the voltage waveforms across {tex} A , B {/tex} and {tex} C {/tex} for a logic circuit with two inputs {tex} A {/tex} and {tex} B {/tex} and output {tex} C . {/tex}<br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/NEET/5dedfa7d2cbd216b6cb2b20c"><br>The logic gate is
Question 26 :
The energy gap between the conduction band and the valence band in a material is 0.07 eV. It is
Question 27 : Truth table for system of four NAND gates as shown in the figure is<br><img style='object-fit:contain' src="https://storage.googleapis.com/teachmint/question_assets/NEET/5dedfa492cbd216b6cb2b1d8"><br>
Question 29 :
To a germanium sample, traces of gallium are added as an impurity. The resultant sample would behave like
Question 33 :
Nucleus of an atom whose atomic mass is 24 consists of
Question 35 :
The energy released in the explosion of an atom bomb is mainly due to
Question 38 :
If an element X has mass number and number of proton 8 then identify element X
Question 39 :
An element has number of proton = 7. Then what will be its atomic number?
Question 41 :
When a silver foil (Z=47) was used in an $\alpha $-ray scattering experiment, the number of $\alpha $ partied scattered at $30^{\circ}$ aws found to be 200 per minute. If the silver foil is replaced by aluminium (z=13) foil of same thickness, the number of $\alpha $-particles scattered per minute at $30^{\circ}$ is nearly equal to
Question 43 :
The density of a nucleus in which mass of each nucleon is $1.67 \times 10^{-27}$ kg and $R_{0}=1.4 \times 10 ^{-15}$ m is :<br>
Question 44 :
If the transition of electron takes place from $n$=4 state, then the maximum number of spectral lines obtained for transition to ground state will be<br>
Question 45 :
The wavelength of spectral line coming from a distant star shifts from 600nm to 600.1 nm. The velocity of the star relative to earth is 
Question 47 :
Electromagnetic waves of wavelength ranging from  $100\overset {\circ}{A}$ to $400 \overset {\circ}{A}$ comes under :<br/>
Question 48 :
The distance of closest approach of the particle to the nucleus will be
Question 49 :
The maximum number of photons emitted by an H-atom,if atom is excited to states with principal quantum number four is<br/>
Question 50 :
The number of waves in the third orbit of H atom is
Question 51 :
Let $v_{1}$ be the frequency of the series limited of the Lyman series, $v_{2}$ be the frequency of the first line of the Lyman series, and $v_{3}$ be the frequency of the series limited of the Balmer series. Then:<br/>
Question 52 :
A neutron of energy $1 MeV$ and mass $1.6\times 10^{-27}$ kg passes a proton at such a distance that the angular momentum of the neutron relative to the proton approximately equals $10^{-33}$ J s. The distance of closest approach neglecting the interaction between particles is<br>
Question 53 :
In an unbiased p-n junction, holes diffuse from the p-region to n-region because of
Question 54 :
An alpha nucleus of energy $\dfrac{1}{2} mv^{2}$ is bombarded onto a heavy nuclear target of charge $Ze$. Then the distance of closest approach for the alpha nucleus will be proportional to
Question 55 :
A common emitter amplifier has a voltage gain of 50, an input impedance of 100{tex} \Omega {/tex} and an output impedance of 200{tex} \Omega . {/tex} The power gain of the amplifier is
Question 56 :
Assertion: Hydrogen atom consists of only one electron but its emission spectrum has many lines.
Reason: Only Lyman series is found in the absorption spectrum of hydrogen atom whereas in the emission spectrum, all the series are found.
Question 57 :
A change of 8.0{tex} \mathrm { mA } {/tex} in the emitter current bring a change of 7.9{tex} \mathrm { mA } {/tex} in the collector current. The values of parameters {tex} \alpha {/tex} and {tex} \beta {/tex} are respectively
Question 58 :
In an experiment on photoelectric effect photons of wavelength $300\ nm$ eject electrons from a metal of work function $2.25\ eV$. A photon of energy equal to that of the most energetic electron corresponds to the following transition in the hydrogen atom.<br>
Question 59 :
Let $\mathrm{v}_{1}$ be the frequency of the series limit for Lyman series, $\mathrm{v}_{2}$ the frequency of the first line of the Lyman series and $\mathrm{v}_{3}$ the frequency of the series limit of Balmer series. Then which of the following relations is true?<br/>
Question 60 :
Actinium 231, {tex}\mathrm{^{231}Ac_{89},}{/tex} emit in succession two {tex}\mathrm{\beta}{/tex} particles, four {tex}\mathrm{\alpha}{/tex}- particles, one {tex}\mathrm{\beta}{/tex} and one {tex}\mathrm{\alpha}{/tex} plus several {tex}\mathrm{\gamma}{/tex} rays. What is the resultant isotope ?
Question 62 :
What initial kinetic energy (in $joule$ and in $MeV$) did the $\alpha$- particle have?<br>
Question 63 :
A hydrogen atoms emits green light when it changes from the n=4 energy level to n=2 level. which color of light would the atom emit when it changes from the n=5 level to n=2 level ?
Question 64 :
If velocity of $\alpha - $particle is made $1/3$ times, then % variation in distance of closest approach will be: (with respect to initial)
Question 65 :
The wave number of first line of Balmer series of hydrogen atom is $15200\ cm^{-1}$. What is the wave number of first line of Balmer series of $Li^{2+}$ ion.
Question 66 :
An alpha particle collides elastically with a stationary nucleus and continues moving at an angle of $60^0$ with respect to the original direction of motion. The nucleus recoils at an angle of $30^0$ with respect to this direction. Mass number of the nucleus is  :
Question 67 :
Assertion: Between any two given energy levels, the number of absorption transitions is always less than the number of emission transitions.
Reason: Absorption transitions start from the lowest energy level only and may end at any higher energy level. But emission transitions may start from anu higher energy level and end at any energy level below it.
Question 68 :
An alpha nucleus of energy $\displaystyle\frac{1}{2}mv^2$ bombards a heavy nuclear target of charge Ze. Then the distance of closest approach for the alpha nucleus will be proportional to
Question 69 :
The current gain for a transistor working as common-base amplifier is {tex}0.96{/tex}. If the emitter current is {tex} 7.2 \mathrm { mA } , {/tex} then the base current is
Question 70 :
The current gain in the common emitter mode of a transistor is 10. The input impedance is 20{tex} \mathrm { k } \Omega {/tex} and load of resistance is 100{tex} \mathrm { k } \Omega . {/tex} The power gain is<br>
