1
JEE Main 2022 (Online) 25th July Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The magnetic moment of an electron (e) revolving in an orbit around nucleus with an orbital angular momentum is given by :

A
$$ \vec{\mu}_{\mathrm{L}}=\frac{\overrightarrow{\mathrm{eL}}}{2 \mathrm{~m}} $$
B
$$\vec{\mu}_{\mathrm{L}}=-\frac{\overrightarrow{\mathrm{eL}}}{2 \mathrm{~m}}$$
C
$$\vec{\mu}_{l}=-\frac{\overrightarrow{e L}}{\mathrm{~m}}$$
D
$$ \vec{\mu}_{l}=\frac{2 \overrightarrow{\mathrm{eL}}}{\mathrm{m}} $$
2
JEE Main 2022 (Online) 30th June Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

A hydrogen atom in ground state absorbs 12.09 eV of energy. The orbital angular momentum of the electron is increased by :

A
1.05 $$\times$$ 10$$-$$34 Js
B
2.11 $$\times$$ 10$$-$$34 Js
C
3.16 $$\times$$ 10$$-$$34 Js
D
4.22 $$\times$$ 10$$-$$34 Js
3
JEE Main 2022 (Online) 29th June Evening Shift
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Change Language

In the following nuclear reaction,

$$D\buildrel \alpha \over \longrightarrow {D_1}\buildrel {{\beta ^ - }} \over \longrightarrow {D_2}\buildrel \alpha \over \longrightarrow {D_3}\buildrel \gamma \over \longrightarrow {D_4}$$

Mass number of D is 182 and atomic number is 74. Mass number and atomic number of D4 respectively will be _________.

A
174 and 71
B
174 and 69
C
172 and 69
D
172 and 71
4
JEE Main 2022 (Online) 29th June Morning Shift
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Change Language

The activity of a radioactive material is 2.56 $$\times$$ 10$$-$$3 Ci. If the half life of the material is 5 days, after how many days the activity will become 2 $$\times$$ 10$$-$$5 Ci ?

A
30 days
B
35 days
C
40 days
D
25 days
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