1
WB JEE 2021
MCQ (Single Correct Answer)
+2
-0.5
Change Language
The atomic masses of helium and neon are 4.0 and 20.0 amu respectively. The value of the de-Broglie wavelength of helium gas at $$-$$73$$^\circ$$C is M times the de-Broglie wavelength of neon at 727$$^\circ$$C. The value of M is
A
5
B
25
C
$${1 \over {5}}$$
D
$${1 \over {25}}$$
2
WB JEE 2020
MCQ (Single Correct Answer)
+1
-0.25
Change Language
The maximum number of electrons in an atom in which the last electron filled has the quantum numbers n = 3, l = 2 and m = $$ - $$ 1 is
A
17
B
27
C
28
D
30
3
WB JEE 2020
MCQ (Single Correct Answer)
+1
-0.25
Change Language
The radius of the first Bohr orbit of a hydrogen atom is 0.53 $$\times {10^-8}$$ cm. The velocity of the electron in the first Bohr orbit is
A
$$2.188 \times {10^8}$$ cm s-1
B
$$4.376 \times {10^8}$$ cm s-1
C
$$1.094 \times {10^8}$$ cm s-1
D
$$2.188 \times {10^9}$$ cm s-1
4
WB JEE 2020
MCQ (Single Correct Answer)
+1
-0.25
Change Language
The number of unpaired electrons in the uranium (92U) atom is
A
4
B
6
C
3
D
1
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