1
JEE Main 2022 (Online) 28th June Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

Let K1 and K2 be the maximum kinetic energies of photo-electrons emitted when two monochromatic beams of wavelength $$\lambda$$1 and $$\lambda$$2, respectively are incident on a metallic surface. If $$\lambda$$1 = 3$$\lambda$$2 then :

A
$${K_1} > {{{K_2}} \over 3}$$
B
$${K_1} < {{{K_2}} \over 3}$$
C
$${K_1} = {{{K_2}} \over 3}$$
D
$${K_2} = {{{K_1}} \over 3}$$
2
JEE Main 2022 (Online) 28th June Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The de Broglie wavelengths for an electron and a photon are $$\lambda$$e and $$\lambda$$p respectively. For the same kinetic energy of electron and photon, which of the following presents the correct relation between the de Broglie wavelengths of two ?

A
$${\lambda _p} \propto \lambda _e^2$$
B
$${\lambda _p} \propto {\lambda _e}$$
C
$${\lambda _p} \propto \sqrt {{\lambda _e}} $$
D
$${\lambda _p} \propto \sqrt {{1 \over {{\lambda _e}}}} $$
3
JEE Main 2022 (Online) 27th June Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

An $$\alpha$$ particle and a carbon 12 atom has same kinetic energy K. The ratio of their de-Broglie wavelengths $$({\lambda _\alpha }:{\lambda _{C12}})$$ is :

A
$$1:\sqrt 3 $$
B
$$\sqrt 3 :1$$
C
$$3:1$$
D
$$2:\sqrt 3 $$
4
JEE Main 2022 (Online) 26th June Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

A metal surface is illuminated by a radiation of wavelength 4500 $$\mathop A\limits^o $$. The ejected photo-electron enters a constant magnetic field of 2 mT making an angle of 90$$^\circ$$ with the magnetic field. If it starts revolving in a circular path of radius 2 mm, the work function of the metal is approximately :

A
1.36 eV
B
1.69 eV
C
2.78 eV
D
2.23 eV
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