1
JEE Main 2018 (Offline)
+4
-1
An electron from various excited states of hydrogen atom emit radiation to come to the ground state. Let $${\lambda _n}$$, $${\lambda _g}$$ be the de Broglie wavelength of the electron in the nth state and the ground state respectively. Let $${\Lambda _n}$$ be the wavelength of the emitted photon in the transition from the nth state to the ground state. For large n, (A, B are constants)
A
$${\Lambda _n} \approx A + {B \over {\lambda _n^2}}$$
B
$${\Lambda _n} \approx A + B{\lambda _n}$$
C
$$\Lambda _n^2 \approx A + B\lambda _n^2$$
D
$$\Lambda _n^2 \approx \lambda$$
2
JEE Main 2018 (Offline)
+4
-1
If the series limit frequency of the Lyman series is $${\nu _L}$$, then the series limit frequency of the Pfund series is:
A
$${\nu _L}/25$$
B
$$25{\nu _L}$$
C
$$16{\nu _L}$$
D
$${\nu _L}/16$$
3
JEE Main 2018 (Offline)
+4
-1
It is found that if a neutron suffers an elastic collinear collision with deuterium at rest, fractional loss of its energy is pd; while for its similar collision with carbon nucleus at rest, fractional loss of energy is pc. The values of pd and pc are respectively :
A
(0, 1)
B
(0.89, 0.28)
C
(0.28, 0.89)
D
(0, 0)
4
JEE Main 2018 (Online) 15th April Evening Slot
+4
-1
An unstable heavy nucleus at rest breaks into two nuclei which move away with velocities in the ratio of 8 : 27. The ratio of the radii of the nuclei (assumed to be spherical) is :
A
8 : 27
B
4 : 9
C
3 : 2
D
2 : 3
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