1
JEE Main 2021 (Online) 25th July Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
A particle of mass 4M at rest disintegrates into two particles of mass M and 3M respectively having non zero velocities. The ratio of de-Broglie wavelength of particle of mass M to that of mass 3M will be :
A
1 : 3
B
3 : 1
C
1 : $$\sqrt 3 $$
D
1 : 1
2
JEE Main 2021 (Online) 22th July Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
An electron of mass me and a proton of mass mp are accelerated through the same potential difference. The ratio of the de-Broglie wavelength associated with the electron to that with the proton is
A
$${{{m_e}} \over {{m_p}}}$$
B
1
C
$${{{m_p}} \over {{m_e}}}$$
D
$$\sqrt {{{{m_p}} \over {{m_e}}}} $$
3
JEE Main 2021 (Online) 20th July Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
An electron having de-Broglie wavelength $$\lambda$$ is incident on a target in a X-ray tube. Cut-off wavelength of emitted X-ray is :
A
0
B
$${{2{m^2}{c^2}{\lambda ^2}} \over {{h^2}}}$$
C
$${{2mc{\lambda ^2}} \over h}$$
D
$${{hc} \over {mc}}$$
4
JEE Main 2021 (Online) 20th July Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
The radiation corresponding to 3 $$\to$$ 2 transition of a hydrogen atom falls on a gold surface to generate photoelectrons. The electrons are passed through a magnetic field of 5 $$\times$$ 10$$-$$4 T. Assume that the radius of the largest circular path followed by these electrons is 7 mm, the work function of the metal is : (Mass of electron = 9.1 $$\times$$ 10$$-$$31 kg)
A
1.36 eV
B
1.88 eV
C
0.82 eV
D
0.16 eV
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