1
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
$${\lambda _p} \propto \sqrt {{1 \over {{\lambda _e}}}} $$
2
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
$$2:\sqrt 3 $$
3
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
4
JEE Main 2022 (Online) 26th June Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

An electron with speed v and a photon with speed c have the same de-Broglie wavelength. If the kinetic energy and momentum of electron are Ee and pe and that of photon are Eph and pph respectively. Which of the following is correct?

A
$${{{E_e}} \over {{E_{ph}}}} = {{2c} \over v}$$
B
$${{{E_e}} \over {{E_{ph}}}} = {v \over {2c}}$$
C
$${{{p_e}} \over {{p_{ph}}}} = {{2c} \over v}$$
D
$${{{p_e}} \over {{p_{ph}}}} = {v \over {2c}}$$
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