1
JEE Main 2019 (Online) 9th April Evening Slot
MCQ (Single Correct Answer)
+4
-1
A He+ ion is in its first excited state. Its ionization energy is :-
A
13.60 eV
B
6.04 eV
C
48.36 eV
D
54.40 eV
2
JEE Main 2019 (Online) 9th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Taking the wavelength of first Balmer line in hydrogen spectrum (n = 3 to n = 2) as 660 nm, the wavelength of the 2nd Balmer line (n = 4 to n = 2) will be :
A
642.7 nm
B
488.9 nm
C
889.2 nm
D
388.9 nm
3
JEE Main 2019 (Online) 8th April Evening Slot
MCQ (Single Correct Answer)
+4
-1
The ratio of mass densities of nuclei of 40Ca and 16O is close to :-
A
1
B
5
C
0.1
D
2
4
JEE Main 2019 (Online) 8th April Morning Slot
MCQ (Single Correct Answer)
+4
-1
Radiation coming from transitions n = 2 to n = 1 of hydrogen atoms fall on He+ ions in n = 1 and n = 2 states. The possible transition of helium ions as they absorb energy from the radiation is :
A
n = 1 $$ \to $$ n = 4
B
n = 2 $$ \to $$ n = 5
C
n = 2 $$ \to $$ n = 4
D
n = 2 $$ \to $$ n = 3
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