1
JEE Advanced 2021 Paper 2 Online
MCQ (More than One Correct Answer)
+4
-2
A heavy nucleus N, at rest, undergoes fission N $$\to$$ P + Q, where P and Q are two lighter nuclei. Let $$\delta$$ = MN $$-$$ MP $$-$$ MQ, where MP, MQ and MN are the masses of P, Q and N, respectively. EP and EQ are the kinetic energies of P and Q, respectively. The speeds of P and Q are vP and vQ, respectively. If c is the speed of light, which of the following statement(s) is(are) correct?
A
$${E_P} + {E_Q} = {c^2}\delta$$
B
$${E_P} = \left( {{{{M_P}} \over {{M_P} + {M_Q}}}} \right){c^2}\delta$$
C
$${{{v_P}} \over {{v_Q}}} = {{{M_Q}} \over {{M_P}}}$$
D
The magnitude of momentum for P as well Q is $$c\sqrt {2\mu \delta }$$, where $$\mu = {{{M_P}{M_Q}} \over {({M_P} + {M_Q})}}$$
2
JEE Advanced 2021 Paper 1 Online
MCQ (More than One Correct Answer)
+4
-2
Which of the following statement(s) is(are) correct about the spectrum of the hydrogen atom?
A
The ratio of the longest wavelength to the shortest wavelength in Balmer series is 9/5
B
There is an overlap between the wavelength ranges of Balmer and Paschen series
C
The wavelengths of Lyman series are given by $$\left( {1 + {1 \over {{m^2}}}} \right){\lambda _0}$$, where $${\lambda _0}$$ is the shortest wavelength of Lyman series and m is an integer
D
The wavelength ranges of Lyman and Balmer series do not overlap
3
JEE Advanced 2020 Paper 2 Offline
MCQ (More than One Correct Answer)
+4
-2
In an X-ray tube, electrons emitted from a filament (cathode) carrying current I hit a target (anode) at a distance d from the cathode. The target is kept at a potential V higher than the cathode resulting in emission of continuous and characteristic X-rays. If the filament current I is decreased to $${1 \over 2}$$, the potential difference V is increased to 2V, and the separation distance d is reduced to $${d \over 2}$$, then
A
the cut-off wavelength will reduce to half, and the wavelengths of the characteristic X-rays will remain the same
B
the cut-off wavelength as well as the wavelengths of the characteristic X-rays will remain the same
C
the cut-off wavelength will reduce to half, and the intensities of all the X-rays will decrease
D
the cut-off wavelength will become two times larger, and the intensity of all the X-rays will decrease
4
JEE Advanced 2020 Paper 1 Offline
MCQ (More than One Correct Answer)
+4
-2
A particle of mass m moves in circular orbits with potential energy V(r) = Fr, where F is a positive constant and r is its distance from the origin. Its energies are calculated using the Bohr model. If the radius of the particle’s orbit is denoted by R and its speed and energy are denoted by v and E, respectively, then for the nth orbit (here h is the Planck’s constant)
A
$$R \propto {n^{{1 \over 3}}}$$ and $$v \propto {n^{{2 \over 3}}}$$
B
$$R \propto {n^{{2 \over 3}}}$$ and $$v \propto {n^{{1 \over 3}}}$$
C
$$E = {3 \over 2}{\left( {{{{n^2}{h^2}{F^2}} \over {4{\pi ^2}m}}} \right)^{{1 \over 3}}}$$
D
$$E = 2{\left( {{{{n^2}{h^2}{F^2}} \over {4{\pi ^2}m}}} \right)^{{1 \over 3}}}$$
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