1
AP EAPCET 2025 - 22nd May Morning Shift
MCQ (Single Correct Answer)
+1
-0

The wavenumber of the first line $\left(n_2=3\right)$ in the Balmer series of hydrogen is overline $\bar{v}_1 \mathrm{~cm}^{-1}$. What is the wavenumber (in $\mathrm{cm}^{-1}$ ) of the second line ( $n_2=4$ ) in the Balmer series of $\mathrm{He}^{+}$?

A

$\frac{5 \bar{V}_1}{27}$

B

$\frac{27 \bar{V}_1}{5}$

C

$\frac{27 \bar{v}_1}{20}$

D

$\frac{20 \bar{v}_1}{27}$

2
AP EAPCET 2025 - 22nd May Morning Shift
MCQ (Single Correct Answer)
+1
-0

Which of the following sets of quantum numbers is not possible for the electron?

A

$n=3, I=1, m=0, s=+\frac{1}{2}$

B

$n=4, I=0, m=0, s=-\frac{1}{2}$

C

$n=3, I=3, m=-3, s=+\frac{1}{2}$

D

$n=1, l=0, m=0, s=-\frac{1}{2}$

3
AP EAPCET 2025 - 22nd May Morning Shift
MCQ (Single Correct Answer)
+1
-0

The correct order of atomic radii of $\mathrm{C}, \mathrm{Al}$ and S is

A

$\mathrm{C}<\mathrm{Al}<\mathrm{S}$

B

S $<$ AI $<$ C

C

AI $<$ S $<$ C

D

$\mathrm{C}<\mathrm{S}<\mathrm{Al}$

4
AP EAPCET 2025 - 22nd May Morning Shift
MCQ (Single Correct Answer)
+1
-0

How many of the following molecules / ions have trigonal planar structure?

$$ \mathrm{BO}_3^{3-}, \mathrm{NH}_3, \mathrm{PCl}_3, \mathrm{BCl}_3, \mathrm{ClF}_3, \mathrm{XeO}_3 $$

A

5

B

2

C

4

D

3