1
JEE Main 2021 (Online) 20th July Evening Shift
+4
-1
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
$${{hc} \over {mc}}$$
2
JEE Main 2021 (Online) 20th July Morning Shift
+4
-1
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
3
JEE Main 2021 (Online) 17th March Evening Shift
+4
-1
Two identical photocathodes receive the light of frequencies f1 and f2 respectively. If the velocities of the photo-electrons coming out are v1 and v2 respectively, then
A
$${v_1} - {v_2} = {\left[ {{{2h} \over m}({f_1} - {f_2})} \right]^{{1 \over 2}}}$$
B
$$v_1^2 + v_2^2 = {{2h} \over m}[{f_1} + {f_2}]$$
C
$${v_1} + {v_2} = {\left[ {{{2h} \over m}({f_1} + {f_2})} \right]^{{1 \over 2}}}$$
D
$$v_1^2 - v_2^2 = {{2h} \over m}[{f_1} - {f_2}]$$
4
JEE Main 2021 (Online) 16th March Morning Shift
+4
-1
The stopping potential in the context of photoelectric effect depends on the following property of incident electromagnetic radiation :
A
Phase
B
Frequency
C
Amnplitude
D
Intensity
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