1
JEE Main 2025 (Online) 22nd January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Given below are two statements :

Statement (I) : A spectral line will be observed for a $2 p_x \rightarrow 2 p_y$ transition.

Statement (II) : $2 \mathrm{p}_x$ and $2 \mathrm{p}_y$ are degenerate orbitals.

In the light of the above statements, choose the correct answer from the options given below :

A
Statement I is false but Statement II is true
B
Both Statement I and Statement II are false
C
Statement I is true but Statement II is false
D
Both Statement I and Statement II are true
2
JEE Main 2025 (Online) 22nd January Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Radius of the first excited state of Helium ion is given as : $\mathrm{a}_0 \rightarrow$ radius of first stationary state of hydrogen atom.

A
$\mathrm{r}=\frac{\mathrm{a}_0}{4}$
B
$\mathrm{r}=2 \mathrm{a}_0$
C
$\mathrm{r}=4 \mathrm{a}_0$
D
$\mathrm{r=\frac{a_0}{2}}$
3
JEE Main 2024 (Online) 9th April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The candela is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency '$$A$$' $$\times 10^{12}$$ hertz and that has a radiant intensity in that direction of $$\frac{1}{{ 'B'}}$$, watt per steradian. '$$A$$' and '$$B$$' are respectively

A
450 and 683
B
540 and $$\frac{1}{683}$$
C
540 and 683
D
450 and $$\frac{1}{683}$$
4
JEE Main 2024 (Online) 9th April Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Compare the energies of following sets of quantum numbers for multielectron system.

(A) $$\mathrm{n}=4,1=1$$

(B) $$\mathrm{n}=4,1=2$$

(C) $$\mathrm{n}=3, \mathrm{l}=1$$

(D) $$\mathrm{n}=3,1=2$$

(E) $$\mathrm{n}=4,1=0$$

Choose the correct answer from the options given below :

A
$$ (\mathrm{E})>(\mathrm{C})>(\mathrm{A})>(\mathrm{D})>(\mathrm{B}) $$
B
$$ (\mathrm{B})>(\mathrm{A})>(\mathrm{C})>(\mathrm{E})>(\mathrm{D}) $$
C
$$ (\mathrm{C})<(\mathrm{E})<(\mathrm{D})<(\mathrm{A})<(\mathrm{B}) $$
D
$$ (\mathrm{E})<(\mathrm{C})<(\mathrm{D})<(\mathrm{A})<(\mathrm{B}) $$
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