NEET - Grade 12 - Chemistry - Haloalkanes and Haloarenes - Study ref# 9935
Match the items of Column I and Column
II.
| read moreNEET - Grade 12 - Chemistry - Alcohols, Phenols and Ethers - Study ref# 9937How many alcohols with molecular formula
C4H10O are chiral in nature?
a)
1
read more NEET - Grade 12 - Chemistry - Amines - Study ref# 9996Best method for preparing primary amines
from alkyl halides without changing the number of carbon atoms in the chains
is
(a) Hofmann bromamide reaction (b)
Gabriel phthalimide synthesis
(c) Sandmeyer
r... read moreNEET - Grade 12 - Chemistry - Biomolecules - Study ref# 10015Structure of disaccharide formed by
glucose and fructose is given below. Identify anomeric carbon atoms in
monosaccharide units.
(a) ‘a’ carbon of glucose and ‘a’ carbon
of fructose
(b) ‘a’ carbon of glucose and ‘e’ carbon
of fr... read moreNEET - Grade 12 - Chemistry - Biomolecules - Study ref# 10019How do you explain the presence of all
the six carbon atoms in glucose in a straight chain? Answer: Glucose on heating with HI produces
n-hexane.
This suggests that all the six carbon
atoms of glucose are linked in a straight chain.... read moreNEET - Grade 12 - Physics - Magnetism and Matter - Study ref# 10530Why does a paramagnetic sample display
greater magnetization (for the same magnetizing field) when cooled? Answer: A paramagnetic sample displays greater
magnetisation when cooled because at the lower temperatures, the tendency to
disrupt th... read moreNEET - Grade 12 - Physics - Atoms - Study ref# 10649Â molecule
consists of two oxygen atoms. In the molecule, nuclear force between the
nuclei of the two atoms
(a) is not important because nuclear
forces are short-ranged.
(b) is as impo... read moreNEET - Grade 12 - Physics - Atoms - Study ref# 10650Two H atoms in the ground state collide
inelastically. The maximum amount by which their combined kinetic energy is
reduced is
(a) 10.20 eVÂ Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â (b)
20.40 eV
(c) 13.6 eVÂ Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
(d) 27.2 eV Answe... read moreNEET - Grade 12 - Physics - Atoms - Study ref# 10651Taking the Bohr radius as =53 pm, the radius of  ion in its ground state, on the
basis of Bohr’s model, will be about
(a) 53 pm.                             Â
(b) 27 pm.
(c) 18 pm.                              (d)
13 pm. Answer: Corre... read moreNEET - Grade 12 - Physics - Atoms - Study ref# 10652The simple Bohr model cannot be directly
applied to calculate the energy levels of an atom with many electrons. This
is because
(a) of the electrons not being subject to
a central force.
(b) of the electrons colliding with each
othe... read moreNEET - Grade 12 - Physics - Atoms - Study ref# 10653For the ground state, the electron in the
H-atom has an angular momentum = Â according to
the simple Bohr model. Angular momentum is a vector and hence there will be
infinitely many orbits with the vector pointing in all possible directions.
... read moreNEET - Grade 12 - Physics - Atoms - Study ref# 10654When is  line
of the Balmer series in the emission spectrum of hydrogen atom obtained? Answer: line
of the Balmer series in the emission spe... read moreNEET - Grade 12 - Physics - Atoms - Study ref# 10655What is the maximum number of spectral
lines emitted by a hydrogen atom when it is in the third excited state?
Answer: If n is the quantum number of highest
energy level, then the total number of possible spectral lines emitted is
... read moreNEET - Grade 12 - Physics - Atoms - Study ref# 10656Define the distance of closest approach.
An  -particle of kinetic energy
ʹKʹ is bombarded on a thin gold foil. The distance of the closest
approach is ʹrʹ. What will be the distance of closest approach for
an  -particl... read moreNEET - Grade 12 - Physics - Atoms - Study ref# 10658The energy levels of a hypothetical atom
are given below. Which of the shown transitions will result in the emission
of photon of wavelength 275 nm?
Answer: (i) Energy of photon corresponding to
wavelength  ,
                         ... read moreNEET - Grade 12 - Physics - Atoms - Study ref# 10659Calculate the de-Broglie wavelength of
the electron orbiting in the n=2 state of hydrogen atom. Answer: Kinetic Energy for the second state
Â
     read moreNEET - Grade 12 - Physics - Atoms - Study ref# 10660Using Rutherford model of the atom,
derive the expression for the total energy of the electron in hydrogen atom. What
is the significance of the total negative energy possessed by the electron? Answer: For hydrogen atom
The coulomb force pro... read moreNEET - Grade 12 - Physics - Atoms - Study ref# 10661Using Bohr’s postulates, derive the
expression for the orbital period of the electron moving in the  orbital of hydrogen atom. Answer:  …Bohr postulate
Also,                        Â
... read moreNEET - Grade 12 - Physics - Atoms - Study ref# 10662(i) Draw a schematic arrangement of
Geiger-Marsden experiment showing the scattering of α-particles
go right through the foil of gold. Why is it that most of the α-particles go right through the foil and only a small fraction
gets ... read moreNEET - Grade 12 - Physics - Atoms - Study ref# 10663In a Geiger- Marsden experiment,
calculate the distance of the closest approach to the nucleus of Z=80, when
an α-particle of 8 MeV energy impinges on it before it comes
momentarily to rest and reverses its direction.
How will the di... read moreNEET - Grade 12 - Physics - Nuclei - Study ref# 10675The gravitational force between a H-atom
and another particle of mass m will be given by Newton’s law:
    Â
(a) Â
(b) read moreNEET - Grade 12 - Physics - Dual Nature of Radiation and Matter - Study ref# 10694(a) In a photoelectric effect, do all the
electrons that absorb a photon come out as photoelectrons irrespective of
their location? Explain
(b) A source of light, of frequency
greater than the threshold frequency, is placed at a distance‘... read moreNEET - Grade 12 - Physics - Semiconductor Electronics: Materials, Devices and Simple Circuits - Study ref# 10704In an n-type silicon, which of the
following statement is true:
(a) Electrons are majority carriers and
trivalent atoms are the dopants.
(b) Electrons are minority carriers and
pentavalent atoms are the dopants.
(c) Holes are min... read moreNEET - Grade 12 - Physics - Semiconductor Electronics: Materials, Devices and Simple Circuits - Study ref# 10709Hole is
(a) an anti-particle of electron,
(b) a vacay created when an electron
leaves a covalent bond.
(c) absence of free electrons.
(d) an artificially created particle. Answer: Correct option: (b)
Explanation: Atoms of semi... read moreNEET - Grade 12 - Biology - Environmental Issues - Study ref# 10774(i) ... read more
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