1
WB JEE 2021
+1
-0.25 A 12.5 eV electron beam is used to bombard gaseous hydrogen at ground state. The energy level upto which the hydrogen atoms would be excited is
A
2
B
3
C
4
D
1
2
WB JEE 2021
+1
-0.25 Let r, v, E be the radius of orbit, speed of electron and total energy of electron respectively in H-atom. Which of the following quantities according to Bohr theory, is proportional to the quantum number n ?
A
vr
B
rE
C
$${r \over E}$$
D
$${r \over v}$$
3
WB JEE 2020
+1
-0.25 If R is the Rydberg constant in cm-1, then hydrogen atom does not emit any radiation of wavelength in the range of
A
$${1 \over R}$$ to $${4 \over {3R}}$$ cm
B
$${7 \over 5R}$$ to $${19 \over {5R}}$$ cm
C
$${4 \over R}$$ to $${36 \over {5R}}$$ cm
D
$${9 \over R}$$ to $${144 \over {7R}}$$ cm
4
WB JEE 2019
+1
-0.25 A proton and an electron initially at rest are accelerated by the same potential difference. Assuming that a proton is 2000 times heavier than an electron, what will be the relation between the de Broglie wavelength of the proton ($$\lambda$$p) and that of electron ($$\lambda$$e)?
A
$$\lambda = 2000{\lambda _e}$$
B
$${\lambda _p} = {{{\lambda _e}} \over {2000}}$$
C
$${\lambda _p} = 20\sqrt 5 {\lambda _e}$$
D
$${\lambda _p} = {{{\lambda _e}} \over {20\sqrt 5 }}$$
WB JEE Subjects
Physics
Mechanics
Electricity
Optics
Modern Physics
Chemistry
Physical Chemistry
Inorganic Chemistry
Organic Chemistry
Mathematics
Algebra
Trigonometry
Coordinate Geometry
Calculus
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