1
JEE Main 2021 (Online) 31st August Evening Shift
+4
-1
A free electron of 2.6 eV energy collides with a H+ ion. This results in the formation of a hydrogen atom in the first excited state and a photon is released. Find the frequency of the emitted photon. (h = 6.6 $$\times$$ 10$$-$$34 Js)
A
1.45 $$\times$$ 1016 MHz
B
0.19 $$\times$$ 1015 MHz
C
1.45 $$\times$$ 109 MHz
D
9.0 $$\times$$ 1027 MHz
2
JEE Main 2021 (Online) 31st August Evening Shift
+4
-1
Consider two separate ideal gases of electrons and protons having same number of particles. The temperature of both the gases are same. The ratio of the uncertainty in determining the position of an electron to that of a proton is proportional to :-
A
$${\left( {{{{m_p}} \over {{m_e}}}} \right)^{3/2}}$$
B
$$\sqrt {{{{m_e}} \over {{m_p}}}}$$
C
$$\sqrt {{{{m_p}} \over {{m_e}}}}$$
D
$${{{m_p}} \over {{m_e}}}$$
3
JEE Main 2021 (Online) 27th August Evening Shift
+4
-1
A monochromatic neon lamp with wavelength of 670.5 nm illuminates a photo-sensitive material which has a stopping voltage of 0.48 V. What will be the stopping voltage if the source light is changed with another source of wavelength of 474.6 nm?
A
0.96 V
B
1.25 V
C
0.24 V
D
1.5 V
4
JEE Main 2021 (Online) 27th August Morning Shift
+4
-1
In a photoelectric experiment, increasing the intensity of incident light :
A
increases the number of photons incident and also increases the K.E. of the ejected electrons
B
increases the frequency of photons incident and increases the K.E. of the ejected electrons
C
increases the frequency of photons incident and the K.E. of the ejected electrons remains unchanged
D
increases the number of photons incident and the K.E. of the ejected electrons remains unchanged
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