WB JEE 2021 | Atoms and Nuclei Question 8 | Physics

WB JEE 2021

MCQ (Single Correct Answer)

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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

WB JEE 2021

MCQ (Single Correct Answer)

-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 ?

$${r \over E}$$

$${r \over v}$$

WB JEE 2020

MCQ (Single Correct Answer)

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If R is the Rydberg constant in cm^-1, then hydrogen atom does not emit any radiation of wavelength in the range of

$${1 \over R}$$ to $${4 \over {3R}}$$ cm

$${7 \over 5R}$$ to $${19 \over {5R}}$$ cm

$${4 \over R}$$ to $${36 \over {5R}}$$ cm

$${9 \over R}$$ to $${144 \over {7R}}$$ cm

WB JEE 2019

MCQ (Single Correct Answer)

-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)?

$$\lambda = 2000{\lambda _e}$$

$${\lambda _p} = {{{\lambda _e}} \over {2000}}$$

$${\lambda _p} = 20\sqrt 5 {\lambda _e}$$

$${\lambda _p} = {{{\lambda _e}} \over {20\sqrt 5 }}$$

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