Physics
GATE PH kind:question PYQs
Build your understanding with focused practice from past exam papers.
Questions 381–390 of 650. Imported answers require independent review unless marked reviewed.
Question 46
Open questionPHMSQ2 marksNeeds review
The time derivative of a differentiable function
is added to a Lagrangian
such that
where
are the generalized coordinates, generalized velocities and time, respectively. Let
be the generalized momentum and
the Hamiltonian associated with
. If
and
are those associated with
, then the correct option(s) is(are)Your answerSelect all correct options. You can choose more than one.
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Open questionPHNAT2 marksNeeds review
A linear charged particle accelerator is driven by an alternating voltage source operating at 10 MHz. Assume that it is used to accelerate electrons. After a few drift-tubes, the electrons attain a velocity 2.9 × 10^8 m s⁻¹. The minimum length of each drift-tube, in m, to accelerate the electrons further (rounded off to one decimal place) is _____.
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Open questionPHNAT2 marksNeeds review
The Coulomb energy component in the binding energy of a nucleus is 18.432 MeV. If the radius of the uniform and spherical charge distribution in the nucleus is 3 fm, the corresponding atomic number (rounded off to the nearest integer) is _____.
(Given:
MeV fm)Log in to check the answer
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Open questionPHNAT2 marksNeeds review
For a two-nucleon system in spin singlet state, the spin is represented through the Pauli matrices
for particles 1 and 2, respectively.
The value of
(in integer) is _____.Log in to check the answer
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Open questionPHNAT2 marksNeeds review
A contour integral is defined as
where
is a positive integer and
is the closed contour, as shown in the figure, consisting of the line from −100 to 100 and the semicircle traversed in the counter-clockwise sense.The value of
(in integer) is _____. 
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Open questionPHNAT2 marksNeeds review
The normalized radial wave function of the second excited state of hydrogen atom is
where
is the Bohr radius and
is the distance from the center of the atom. The distance at which the electron is most likely to be found is
. The value of
(in integer) is _____.Log in to check the answer
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Open questionPHNAT2 marksNeeds review
Consider an atomic gas with number density
m⁻³, in the ground state at 300 K. The valence electronic configuration of atoms is
. The paramagnetic susceptibility of the gas
. The value of
(rounded off to two decimal places) is _____.(Given: Magnetic permeability of free space
H m⁻¹Bohr magneton
A m²Boltzmann constant
J K⁻¹)Log in to check the answer
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Open questionPHNAT2 marksNeeds review
Consider a cross-section of an electromagnet having an air-gap of 5 cm as shown in the figure. It consists of a magnetic material (
) and is driven by a coil having
A, where
is the number of turns and
is the current in Ampere. 
Ignoring the fringe fields, the magnitude of the magnetic field
(in Tesla, rounded off to two decimal places) in the air-gap between the magnetic poles is _____.Log in to check the answer
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Open questionPHNAT2 marksNeeds review
The spin
and orbital angular momentum
of an atom precess about
, the total angular momentum.
precesses about an axis fixed by a magnetic field
, where
is a constant. Now the magnetic field is changed to
. Given the orbital angular momentum quantum number
and spin quantum number
,
is the angle between
and
for the largest possible values of total angular momentum quantum number
and its z-component
. The value of
(in degree, rounded off to the nearest integer) is _____.Log in to check the answer
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Open questionPHNAT2 marksNeeds review
The spin-orbit effect splits the
transition (wavelength,
Å) in Lithium into two lines with separation of
Å. The corresponding positive value of energy difference between the above two lines, in eV, is
. The value of
(rounded off to the nearest integer) is _____.(Given: Planck’s constant,
eV sSpeed of light,
m s⁻¹)Log in to check the answer
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