1
JEE Main 2020 (Online) 9th January Evening Slot
MCQ (Single Correct Answer)
+4
-1
The energy required to ionise a hydrogen like ion in its ground state is 9 Rydbergs. What is the wavelength of the radiation emitted when the electron in this ion jumps from the second excited state to the ground state ?
A
35.8 nm
B
11.4 nm
C
8.6 nm
D
24.2 nm
2
JEE Main 2020 (Online) 8th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
The graph which depicts the results of Rutherford gold foil experiment with $$\alpha $$-particales is :
$$\theta $$ : Scattering angle
Y : Number of scattered $$\alpha $$-particles detected (Plots are schematic and not to scale)
A
JEE Main 2020 (Online) 8th January Morning Slot Physics - Atoms and Nuclei Question 152 English Option 1
B
JEE Main 2020 (Online) 8th January Morning Slot Physics - Atoms and Nuclei Question 152 English Option 2
C
JEE Main 2020 (Online) 8th January Morning Slot Physics - Atoms and Nuclei Question 152 English Option 3
D
JEE Main 2020 (Online) 8th January Morning Slot Physics - Atoms and Nuclei Question 152 English Option 4
3
JEE Main 2020 (Online) 7th January Evening Slot
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
The activity of a radioactive sample falls from 700 s–1 to 500 s–1 in 30 minutes. Its half life is close to:
A
62 min
B
66 min
C
72 min
D
52 min
4
JEE Main 2020 (Online) 7th January Morning Slot
MCQ (Single Correct Answer)
+4
-1
The time period of revolution of electron in its ground state orbit in a hydrogen atom is 1.6 $$ \times $$ 10-16 s. The frequency of revolution of the electron in its first excited state (in s-1) is :
A
5.6 $$ \times $$ 1012
B
1.6 $$ \times $$ 1014
C
7.8 $$ \times $$ 1014
D
6.2 $$ \times $$ 1015
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