datavorous/entrance-exam-dataset huggingface dataset:
If $\Delta \mathrm{U}$ and $\Delta \mathrm{W}$ represent the increase in internal energy and work done by the system respectively in a thermodynamical process, which of the following is true?

Options:
A $\Delta \mathrm{U}=-\Delta \mathrm{W}$, in a adiabatic process
B $\Delta \mathrm{U}=\Delta \mathrm{W}$, in a isothermal process
C $\Delta \mathrm{U}=\Delta \mathrm{W}$, in a adiabatic process
D $\Delta \mathrm{U}=-\Delta \mathrm{W}$, in a isothermal process

The correct answer is:
$\Delta \mathrm{U}=-\Delta \mathrm{W}$, in a adiabatic process

Solution:
From first law of thermodynamics
$$
\Delta Q=\Delta U+\Delta \mathrm{W}
$$
For adiabatic process $\Delta Q=0$
$$
\Rightarrow \quad \Delta U=-\Delta W
$$

Topic: Physics, Thermodynamics, NEET, NEET 2010 (Screening)
If uncertainty in position and momentum are equal, then uncertainty in velocity is

Options:
A $\frac{1}{2 m} \sqrt{\frac{h}{\pi}}$
B $\sqrt{\frac{h}{2 \pi}}$
C $\frac{1}{m} \sqrt{\frac{h}{\pi}}$
D $\sqrt{\frac{h}{\pi}}$

The correct answer is:
$\frac{1}{2 m} \sqrt{\frac{h}{\pi}}$

Solution:
Key Idea: According to Heisenberg's uncertainty principle, it is impossible to determine simultaneously the position and momentum of a moving microscopic particle, ie,
$\begin{aligned}
& \Delta x \times \Delta p \geq \frac{h}{4 \pi} \\
& \because \Delta x \times \Delta p \geq \frac{h}{4 \pi}
\end{aligned}$
Here $\Delta x=\Delta p$ and $\Delta p=m \cdot \Delta v$
$\begin{aligned}
& \therefore \Delta v^2=\frac{h}{m^2 4 \pi} \\
& \text {or } \\
& \Delta v=\frac{1}{2 m} \sqrt{\frac{h}{\pi}}
\end{aligned}$
Note: The uncertainty principle in terms of energy and time is given as
$\Delta E \cdot \Delta t \geq \frac{h}{4 \pi}$

Topic: Chemistry, Structure of Atom, NEET, NEET 2008 (Screening)
If V and u are electric potential and energy density, respectively, at a distance r from a positive point charge, then which of the following graphs is correct?

Options:
A
B
C
D

The correct answer is:

Solution:
V=kQr
we know that,
u=12ε0E2=12ε0k2Q2r4
∴ V4∝u

Topic: Physics, Electrostatics, NEET
If Î»v , Î»x , and Î»m represent the wavelengths of visible light, X - rays and microwaves respectively, then

Options:
A λm>λx>λv
B λm>λv>λx
C λv>λx>λm
D λv>λm>λx

The correct answer is:
λm>λv>λx

Solution:
We know
E=hcλ ⇒E∝ 1λ
⇒ Em<Ev<Ex
∴ λm>λv>λx

Topic: Physics, Electromagnetic Waves, NEET
If $\lambda_v, \lambda_x$ and $\lambda_m$ represent the wavelength of visible light, X-rays and microwaves respectively, then:

Options:
A $\lambda_m>\lambda_{\mathrm{x}}>\lambda_v$
B $\lambda_m>\lambda_{\mathrm{v}}>\lambda_x$
C $\lambda_v>\lambda_x>\lambda_m$
D $\lambda_v>\lambda_m>\lambda_x$

The correct answer is:
$\lambda_m>\lambda_{\mathrm{v}}>\lambda_x$

Solution:
$\quad \lambda_{\mathrm{m}}>\lambda_v>\lambda_x$
In spectrum $\mathrm{X}$-rays has minimum wavelength and microwave has maximum wavelength

Topic: Physics, Electromagnetic Waves, NEET, NEET 2005
If Vasa efferentia gets blocked, the gametes will not be transported from:

Options:
A Testis to epididymis
B Epididymis to vas deferens
C Vas deferens to ejaculatory duct
D None of these

The correct answer is:
Testis to epididymis

Solution:
Vasa efferentia are fine ciliated ductules that arise from the seminiferous tubules of the testis (where sperms are formed) and open into epididymis which is a mass of long narrow closely coiled tubule lying along the inner side of testis. Epididymis stores the sperms. Thus, if vasa efferentia gets blocked, sperms will not be transported from testis to the epididymis.

Topic: Biology, Human Reproduction, NEET
If vectors A→=cos⁡ωt i^+sinωt j^ and B→=cosωt2 i^+sin⁡ωt2 j^ are functions of time, then the value of t at which they are orthogonal to each other is:

Options:
A t=π2ω
B t=πω
C t=0
D t=π4ω

The correct answer is:
t=πω

Solution:
A→=cos wti^+sinwtj^
B→=coswt2i^+sinwt2j^
For these vectors to be orthogonal, A→·B→=0
A→·B→=0=cos wt.coswt2+sin wt.sin wt2
=coswt-wt2=coswt2=0
So, as we know, \(\cos (90)=0\).
So, wt2=π2⇒ t=πw

Topic: Physics, Mathematics in Physics, NEET, NEET 2015 (Phase 2)
If velocity of a galaxy relative to earth is 1.2Ã106 m s-2 then % increase in wavelength of light from galaxy as compared to the similar source on earth will be

Options:
A 0.3%
B 0.4%
C 0.5%
D 0.6%

The correct answer is:
0.4%

Solution:
Since υc=∆λλ
∴∆λ=υc×λ
Or ∆λλ=1.2×1063×108=123×105108=4×10-3
Δλλ×100=0.4 i.e., 0.4%

Topic: Physics, Wave Optics, NEET
If voltage across a bulb rated $220 \mathrm{~V}-100 \mathrm{~W}$ drops by $2.5 \%$ of its rated value, the percentage of the rated value by which the power would decrease is

Options:
A 20\%
B $2.5 \%$
C $5 \%$
D $10 \%$

The correct answer is:
$5 \%$

Solution:
Power $P=\frac{V^2}{R}$
For small variation
$\begin{aligned}
\frac{\Delta P}{P} \times 100 \% & =\frac{2 \times \Delta V}{V} \times 100 \% \\
& =2 \times 2.5=5 \%
\end{aligned}$
Therefore, power would decrease by $5 \%$.

Topic: Physics, Current Electricity, NEET, NEET 2012 (Screening)
If water contains dissolved calcium hydrogencarbonate, out of soaps and synthetic detergents which one will you use for cleaning clothes?

Options:
A Soaps
B Synthetic Detergents
C Both are equally effective
D Neither will be effective

The correct answer is:
Synthetic Detergents

Solution:
Correct Option is : (B)
Synthetic Detergents

Topic: Chemistry, Chemistry in Everyday Life, NEET
If water potential of a cell is -30 bar and osmotic potential is -62 bar then what is the value of the TP developed in the cell.

Options:
A 102 bar
B –92 bar
C –50 bar
D 32 bar

The correct answer is:
32 bar

Solution:
Pressure potential or turgor pressure of cell is positive hydrostatic pressure exerted due to entry of water into the cell. It is determined by Î¨p = Î¨w â Î¨s = -30 - (-62) = 32 bar

Topic: Biology, Transport in Plants, NEET
If water vapour is assumed to be a perfect gas, the molar enthalpy change for vapourisation of 1 mol of water at 1 bar and 100°C is 41kJ mol–1. Calculate the internal energy change, when 1 mol of water is vapourised at 1 bar pressure and 100°C.

Options:
A 37.904 kJ mol–1
B 35.854 kJ mol–1
C 39.904 kJ mol–1
D 42.575 kJ mol-1

The correct answer is:
37.904 kJ mol–1

Solution:
Correct Option is : (A)
37.904 kJ mol–1

Topic: Chemistry, Thermodynamics (C), NEET
If we accept Robert May's global estimates, only ______ of the total species have been recorded so far.

Options:
A 12%
B 22%
C 32%
D 42%

The correct answer is:
22%

Solution:
Robert May gave a conservative and scientifically correct estimate of global species diversity. According to him there are about 7 million species out of which on 22% have been recorded so far.

Topic: Biology, Biodiversity and its Conservation, NEET
If we add impurity to a metal, those atoms also deflect electrons. Therefore,

Options:
A The electrical and thermal conductivities both increase
B The electrical and thermal conductivities both decrease
C The electrical conductivity increases but thermal conductivity decreases
D The electrical conductivity decrease but thermal conductivity increases

The correct answer is:
The electrical and thermal conductivities both decrease

Solution:
If the number of electrons increases, their number of the collision, increase the thermal and electrical resistance. Hence, electrical and thermal conductivities both decrease.

Topic: Physics, Semiconductors, NEET
If we add impurity to a metal those atoms also deflect electrons. Therefore,

Options:
A The electrical and thermal conductivities both increase
B The electrical and thermal conductivities both decrease
C The electrical conductivity increases but thermal conductivity decreases
D The electrical conductivity decrease but thermal conductivity increases

The correct answer is:
The electrical and thermal conductivities both decrease

Solution:
If the number of electrons increase, their number of collision, increasing the thermal and electrical resistance. Hence, electrical and thermal conductivities both decrease.

Topic: Physics, Semiconductors, NEET
If we completely remove the decomposers from an ecosystem, the ecosystem functioning will be adversely affected because:

Options:
A Mineral movement will be blocked
B Herbivores will not receive solar energy
C Energy flow will be blocked
D Rate of deposition of other component will be very high.

The correct answer is:
Mineral movement will be blocked

Solution:
Heterotrophic organisms like bacteria and fungi act as decomposers which degrade the dead organic matter or detritus which in turn provides energy and nutrition. Decomposers secrete gastric enzymes resulting in the breakdown of dead organic matter into simple inorganic substances which are then absorbed in the soil and used by producers to grow. Hence if the decomposers are removed from the ecosystem, nutrients will not be available to producers which block the flow of minerals from producers to consumers.

Topic: Biology, Ecosystem, NEET
If we introduce the desired gene into the bacteriophage DNA and the bacteriophage is allowed to divide in the bacteria, then the number of copies of the desired gene that can be produced is expected to be:

Options:
A No bacteriophage will be produced.
B Less than the number of bacteriophages produced.
C More than the number of bacteriophages produced.
D Equal to the number of bacteriophages produced

The correct answer is:
Equal to the number of bacteriophages produced

Solution:
Cloning vectors:
- Plasmids and bacteriophages can replicate within bacterial cells. This replication is independent of the control of chromosomal DNA.
- As the number of bacteriophages is very high per cell, their copy numbers of genome is also very high in bacterial cells.
- Number of plasmids per bacteria is usually in range of 15 to 100 but in few cases this may be as low as 1 or 2.
- If we are able to introduce the alien DNA (with desired gene) into a bacteriophage or plasmid DNA, we can multiply the alien DNA in copies equal to that of the bacteriophage or plasmid DNA.

Topic: Biology, Biotechnology - Principles and Processes, NEET
If we observe the structure of proteins, disulphide bonds are formed between

Options:
A Cysteine residues that are close together
B Cystine residues that are close together
C Proline residues that are close together
D Histidine residues that are close together

The correct answer is:
Cysteine residues that are close together

Solution:
Cysteine amino acids are the sulphur containing amino acids and are involved in the formation of disulfide bonds.

Topic: Chemistry, Biomolecules, NEET
If we plot volume of a certain mass of a gas against temperature at constant pressure, we get a straight line interesting on the negative side at -273°C which explains about absolute zero. This graph is known as

Options:
A isochor
B isotherm
C isotone
D isobar

The correct answer is:
isobar

Solution:
The graph between V and T at constant pressure is called isobar.

Topic: Chemistry, States of Matter, NEET
If Wien's constant b=0.3cmâ¡K, then the temperature of the Sun having a maximum intensity of radiation at 5000ââ« wavelength is

Options:
A 5000 K
B 6000 K
C 4000 K
D 7000 K

The correct answer is:
6000 K

Solution:
From Wein's displacement law
λmT=b
5000×10-10×T=0.3×10-2
T=6000 K

Topic: Physics, Thermal Properties of Matter, NEET
If work function of Li > Na > K , predict their values of work function

Options:
A 2.42 , 2.3 , 2.25
B 4.8 , 4.3 , 3.7
C 2.3 , 2.42, 2.25
D 4.8 , 3.7 , 2.3

The correct answer is:
2.42 , 2.3 , 2.25

Solution:
Correct Option is : 1
2.42 , 2.3 , 2.25

Topic: Chemistry, Structure of Atom, NEET
If $x=5 \sin \left(\pi t+\frac{\pi}{3}\right) \mathrm{m}$ represents the motion of a particle executing simple harmonic motion, the amplitude and time period of motion, respectively, are

Options:
A $5 \mathrm{~m}, 2 \mathrm{~s}$
B $5 \mathrm{~cm}, 1 \mathrm{~s}$
C $5 \mathrm{~m}, 1 \mathrm{~s}$
D $5 \mathrm{~cm}, 2 \mathrm{~s}$

The correct answer is:
$5 \mathrm{~m}, 2 \mathrm{~s}$

Solution:
$\begin{aligned} & \therefore x=5 \sin \left(\pi t+\frac{\pi}{3}\right) \mathrm{m} \\ & \text { Amplitude }=5 \mathrm{~m} \\ & \omega=\pi=\frac{2 \pi}{T} \\ & T=\frac{2 \pi}{\pi}=2 \mathrm{~s}\end{aligned}$

Topic: Physics, Oscillations, NEET, NEET 2024
If X=A×B and ∆X and ∆A and ∆B are maximum absolute errors in X, A and B respectively, then the maximum relative error in X is given by

Options:
A ∆X=∆A+∆B
B ∆X=∆A-∆B
C ∆XX=∆AA-∆BB
D ∆XX=∆AA+∆BB

The correct answer is:
∆XX=∆AA+∆BB

Solution:
When two quantities are multiplied, their maximum relative errors are added up.

Topic: Physics, Units and Dimensions, NEET
If $x$ is amount of adsorbate and $m$ is amount of adsorbent, which of the following relations is not related to adsorption process?

Options:
A $\frac{x}{m}=f(T)$ at constant $p$
B $p=f(T)$ at constant $\left(\frac{x}{m}\right)$
C $\frac{x}{m}=p \times T$
D $\frac{x}{m}=f(p)$ at constant $T$

The correct answer is:
$\frac{x}{m}=p \times T$

Solution:
$\frac{x}{m}=p \times T$ is the incorrect relation. The correct relation is $\frac{x}{m} \propto \frac{p}{T}$.

Topic: Chemistry, Surface Chemistry, NEET, NEET 2011 (Screening)
If you are asked to classify the various algae into distinct groups, which of the following characters you should choose?

Options:
A nature of stored food materials in the cell
B structural organization of thallus
C chemical composition of the cell wall
D types of pigments present in the cell.

The correct answer is:
types of pigments present in the cell.

Solution:
Algae are a group of chlorophyllous, nonvascular plants with thallus plant body. Different algae show different pigments present in the cell like chlorophyll - a, b, xanthophylls, carotenes etc. These pigments provide the base for classification of various groups of algae into different classes. Chlorophyceae possess chlorophyll - a, b pigments, Phaeophyceae has fucoxanthin, and Rhodophyceae has r-phycocyanin.

Topic: Biology, Plant Kingdom, NEET, NEET 2007
If you are provided with root-tips of onion in your class and are asked to count the chromosomes. Which of the following stages can you most conveniently took into?

Options:
A metaphase
B telophase
C anaphase
D prophase.

The correct answer is:
metaphase

Solution:
Chromosomal morphology is best observed at metaphase. Metaphase is a stage of mitosis in the cell cycle in which chromosomes are at their most condensed and coiled stage.
Related Theory
In metaphase chromosomes line up at the metaphase plate, under tension from the mitotic spindle. The two sister chromatids of each chromosome are captured by microtubules from opposite spindle poles. In metaphase, the spindle has captured all the chromosomes and lined them up at the middle of the cell, ready to divide.

Topic: Biology, Cell Cycle and Cell Division, NEET, NEET 2004
If you change the stoichiometric coefficients in a chemical equation, how does it affect the equilibrium constant expression?

Options:
A It has no effect on the equilibrium constant expression.
B It causes the equilibrium constant to become zero.
C It alters the numerical value of the equilibrium constant.
D It makes the equilibrium constant undefined.

The correct answer is:
It alters the numerical value of the equilibrium constant.

Solution:
Changing the stoichiometric coefficients in a chemical equation alters the numerical value of the equilibrium constant.

Topic: Chemistry, Chemical Equilibrium, NEET
If you squeeze a seed of orange you might observe many embryos of different sizes. It is because of:

Options:
A

Polyembryony

B

Apomixis

C

Pollination

D

Parthenocarpy

The correct answer is:

Polyembryony

Solution:
In orange seed, nucellar cells surrounding the embryo sac start dividing, protrude into the embryo sac and develop into the embryos. In such species, each ovule contains many embryos. Occurrence of more than one embryo in a seed is referred to as polyembrony.

Topic: Biology, Sexual Reproduction in Flowering Plants, NEET
If you suspect major deficiency of antibodies in a person, to which of the following would you like for confirmation evidence?

Options:
A Serum albumins
B Haemocytes
C Serum globulins
D Fibrinogen in plasma

The correct answer is:
Serum globulins

Solution:
Antibodies are the Y-shaped proteins present in the serum. They are glycoproteins and also called gamma globulins. They are produced through the process of haematopoiesis. Hence, if the antibodies are less then directly they can be interpreted as the serum globulins.

Topic: Biology, Body Fluids and Circulation, NEET, NEET 2015 (Phase 2)
If you suspect major deficiency of antibodies in a person, to which of the following would you like for confirmation evidence?

Options:
A Serum albumins
B Haemocytes
C Serum globulins
D Fibrinogen in plasma

The correct answer is:
Serum globulins

Solution:
Antibodies are present in serum. They are glycoproteins and also called gammaglobulins. If they are produced less through hematopoiesis then their concentration will be less in serum.

Topic: Biology, Human Health and Diseases, NEET
If you suspect major deficiency of antibodies in a person, to which of the following would you look for confirmatory evidence?

Options:
A serum globulins
B fibrinogen in the plasma
C haemocytes
D serum albumins.

The correct answer is:
serum globulins

Solution:
Chemically, antibodies are globular proteins, belong to a class of serum proteins, which are called $\gamma$ or gamma globulins. Thus, the antibodies are also known as immunoglobulins and are produced by the lymphocytes. Hence, to confirm the deficiency of antibodies in a person, serum globulins will be tested.
Related Theory
Blood proteins, also termed plasma proteins, are proteins present in blood plasma. 90-92 per cent of plasma is water and proteins contribute 6-8 per cent of it. Fibrinogen, globulins and albumins are the major proteins. Fibrinogens are needed for clotting or coagulation of blood. Globulins primarily are involved in defense mechanisms of the body and the albumins help in osmotic balance.

Topic: Biology, Body Fluids and Circulation, NEET, NEET 2007
If Young's modulus of the material is three times of its modulus of rigidity, then its volume elasticity will be

Options:
A Zero
B 3Ã1011 N m-2
C Infinity
D 10.6Ã1011 N m-2

The correct answer is:
Infinity

Solution:
Since, we know,
Y=2η1+σ ...(i)
Where, Y= Young's modulus and η= modulus of rigidity.
Given, Y=3η
From Equation (i), we get
3η=2η1+σ
⇒1+σ=32
⇒σ=1/2
∴ Bulk modulus, K=Y3(1-2σ)
Thus, K=Y31-2×12=Y3(1-1)=∞
Thus, volume elasticity is infinity.

Topic: Physics, Mechanical Properties of Solids, NEET
If $Z_1$ and $Z_2$ are the impedances of the given circuits (a) and (b) as shown in figures, then choose the correct option.

Options:
A $Z_1=Z_2$
B $Z_1>Z_2$
C $Z_1 < Z_2$
D $Z_1+Z_2=20 \Omega$

The correct answer is:
$Z_1 < Z_2$

Solution:
$Z_1=R=10 \Omega$ [as, D.C. voltage is supplied]
$Z_2=\sqrt{R^2+\left(X_C\right)^2}=\sqrt{(10)^2+\left[\frac{1}{2 \times \pi \times 50 \times \frac{10^3}{\pi} \times 10^{-6}}\right]^2}$
$\begin{aligned} & \Rightarrow Z_2=\sqrt{(10)^2+(10)^2}=10 \sqrt{2} \\ & \Rightarrow Z_2>Z_1 \text { or } Z_1 < Z_2\end{aligned}$

Topic: Physics, Alternating Current, NEET, NEET 2023 (Manipur)
If Z<1, then gas is at

Options:
A High pressure
B Low pressure
C Intermediate pressure
D None of the above

The correct answer is:
Intermediate pressure

Solution:
Correct Option is : 3
Intermediate pressure

Topic: Chemistry, States of Matter, NEET
â (ii)â H 2 O 2 ,â OH â (i)â BH 3 ,âTHF (A); Product 'A' of the reaction is

Options:
A
B
C
D

The correct answer is:

Solution:
This reaction occurs according to Antimarkonikov rule and addition takes place via syn addition.

Topic: Chemistry, Hydrocarbons, NEET
Ileocecal valve prevents the backflow of fecal matter from

Options:
A Ileum to caecum
B Caecum to ileum
C Ileum to jejunum
D Caecum to vermiform appendix

The correct answer is:
Caecum to ileum

Solution:
There is no significant digestive activity in the large intestine.
Functions of the large intestine are,
(i) Absorption of some water and minerals.
(ii) Absorption of certain drugs.
(iii) Secretion of mucus which keeps the waste (undigested) particles together in the form of faeces and lubricates it for an easy passage.
Faeces enter the caecum through the ileocaecal valve. This valve prevents the backflow of faecal matter into the ileum.

Topic: Biology, Digestion and Absorption, NEET
Illustrate by taking examples of transition elements and non-transition elements that oxidation states of elements are largely based on electronic configuration.

Options:
A Transition elements exhibit variable oxidation states due to the availability of multiple valence electrons.
B Non-transition elements have fixed oxidation states as their valence electrons are not involved in bonding.
C Both transition and non-transition elements show fixed oxidation states regardless of their electronic configuration.
D Oxidation states of elements are determined solely by their position in the periodic table.

The correct answer is:
Transition elements exhibit variable oxidation states due to the availability of multiple valence electrons.

Solution:
Correct Option is : (A)
Transition elements exhibit variable oxidation states due to the availability of multiple valence electrons.

Topic: Chemistry, Classification of Elements and Periodicity in Properties, NEET
Illustrate how copper metal can give different products on reaction with HNO3.

Options:
A Cu + 4HNO3→ Cu(NO3)2+ 2NO2+ 2H2O
B 3Cu + 8HNO3→ 3Cu(NO3)2+ 2NO + 4H2O
C 3Cu + 2HNO3→ 3CuO + 2NO + H2O
D 2Cu + 4HNO3→ 2Cu(NO3)2+ 2H2O

The correct answer is:
3Cu + 8HNO3→ 3Cu(NO3)2+ 2NO + 4H2O

Solution:
Correct Option is : (B)
3Cu + 8HNO3→ 3Cu(NO3)2+ 2NO + 4H2O

Topic: Chemistry, p Block Elements (Group 13 & 14), NEET
Imagine a light planet revolving around a very massive star in a circular orbit of radius R with a period of revolution T. If the gravitational force of attraction between the planet and the star is proportional to R-52, then

Options:
A T2 is proportional to R2
B T2 is proportional to R72
C T2 is proportional to R32
D T2 is proportional to R52

The correct answer is:
T2 is proportional to R72

Solution:
Given, F = K R-52
We know, F = mω2R
⇒ ω2∝R-72
⇒ T2∝R72 ( since T∝1ω )

Topic: Physics, Gravitation, NEET
Imagine a new planet having the same density as that of earth but it is 3 times bigger than the earth in size. If the acceleration due to gravity on the surface of earth is $g$ and that on the surface of the new planet is $\mathrm{g}^{\prime}$ then:

Options:
A $g^{\prime}=\frac{g}{9}$
B $g^{\prime}=27 g$
C $g^{\prime}=9 g$
D $g^{\prime}=3 g$

The correct answer is:
$g^{\prime}=3 g$

Solution:
$\begin{aligned}
g=\frac{G M}{R^2} & =\frac{G \frac{4}{3} \pi R^3 \rho}{R^2} \\
& =\frac{4}{3} G \pi R \rho \\
g^{\prime} & =\frac{4}{3} G \pi(3 R) \rho \\
& =3 g
\end{aligned}$

Topic: Physics, Gravitation, NEET, NEET 2005
Imagine an atom made of a nucleus of charge Ze and a hypothetical particle of the same mass but double the charge of the electron. Apply the Bohr atom model and consider all possible transitions of this hypothetical particle to the ground state. The longest wavelength of a photon that will be emitted has wavelength λ (Given in terms of Rydberg constant RH of the hydrogen atom) equal to

Options:
A 14Z2RH
B 13Z2RH
C 43Z2RH
D 4Z2RH

The correct answer is:
13Z2RH

Solution:
Longest wavelength n=2 to n=1
mv2r=k.Ze(2e)r2
mvr=nh2π
Kinetic energy, potential energy and total energy becomes four times
∴ ΔE becomes four times
∴ ΔE=4Z2RHch112-122 (c is the speed of light)
ΔE=3RHchZ2
hcλ=3RHchZ2
λ=13Z2RH

Topic: Physics, Atomic Physics, NEET
Imagine that a reactor converts all the given mass into energy and that it operates at a power level of 109 watt. The mass of the fuel consumed per hour, in the reactor, will be
(velocity of light, c is 3Ã108 m s-1 )

Options:
A 6.6Ã10-5 g
B 0.96Â g
C 4Ã10-2 g
D 0.8Â g

The correct answer is:
4Ã10-2 g

Solution:
P=EÎt=Îmc2Ît
âmât=Pc2 =1093Ã1082
â âmât=10-79 kg s-1
=10-79Ã1000 g3600 h-1=4Ã10-2 g h-1

Topic: Physics, Nuclear Physics, NEET