1
WB JEE 2008
MCQ (Single Correct Answer)
+1
-0.25

The ionisation potential of hydrogen atom is $$-$$13.6 eV. An electron in the ground state of a hydrogen atom absorbs a photon of energy 12.75 eV. How many different spectral lines can one expect when the electron make a downward transition?

A
1
B
4
C
2
D
6
2
WB JEE 2008
MCQ (Single Correct Answer)
+1
-0.25

Which of the following statements is correct?

A
The rest mass of a stable nucleus is less than the sum of the rest masses of its separated nucleons.
B
The rest mass of a stable nucleus is greater than the sum of the rest masses of its separated nucleons.
C
In nuclear fission, energy is released by fusion is two nuclei of medium mass (approximately 100 amu)
D
In nuclear fission, energy is released by fragmentation of a very low nucleus.
3
WB JEE 2025
MCQ (Single Correct Answer)
+1
-0.25
Change Language

A radioactive nucleus decays as follows :

$$ X \xrightarrow{\alpha} X_1 \xrightarrow{\beta} X_2 \xrightarrow{\alpha} X_3 \xrightarrow{\gamma} X_4 $$

If the mass number and atomic number of ' $X_4$ ' are 172 and 69 respectively, then the atomic number and mass number of ' $X$ ' are

A
72,180
B
69,170
C
68,172
D
70,172
4
WB JEE 2025
MCQ (Single Correct Answer)
+1
-0.25
Change Language

The minimum wavelength of Lyman series lines is $P$, then the maximum wavelength of these lines is

A
$\frac{4 P}{3}$
B
$2 P$
C
$\frac{2 P}{3}$
D
$\infty$
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