1
JEE Main 2021 (Online) 25th February Evening Shift
+4
-1
An electron of mass me and a proton of mass mp = 1836 me are moving with the same speed. The ratio of their de Broglie wavelength $${{{}^\lambda electron} \over {{}^\lambda proton}}$$ will be :
A
1
B
1836
C
$${1 \over {1836}}$$
D
918
2
JEE Main 2021 (Online) 25th February Morning Slot
+4
-1
Two radioactive substances X and Y originally have N1 and N2 nuclei respectively. Half life of X is half of the half life of Y. After three half lives of Y, number of nuclei of both are equal. The ratio $${{{N_1}} \over {{N_2}}}$$ will be equal to :
A
$${1 \over 8}$$
B
$${3 \over 1}$$
C
$${1 \over 3}$$
D
$${8 \over 1}$$
3
JEE Main 2021 (Online) 24th February Evening Slot
+4
-1
The de-Broglie wavelength of a proton and $$\alpha$$-particle are equal. The ratio of their velocities is :
A
4 : 2
B
4 : 3
C
4 : 1
D
1 : 4
4
JEE Main 2021 (Online) 24th February Morning Slot
+4
-1
In the given figure, the energy levels of hydrogen atom have been shown along with some transitions marked A, B, C, D and E.

The transitions A, B and C respectively represent :

A
The series limit of Lyman series, second member of Balmer series and second member of Paschen series.
B
The ionization potential of hydrogen, second member of Balmer series and third member of Paschen series.
C
The series limit of Lyman series, third member of Balmer series and second member of Paschen series.
D
The first member of the Lyman series, third member of Balmer series and second member of Paschen series.
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