1
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
$${{hc} \over {mc}}$$
2
JEE Main 2021 (Online) 20th July Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
A body rolls down an inclined plane without slipping. The kinetic energy of rotation is 50% of its translational kinetic energy. The body is :
A
Solid sphere
B
Solid cylinder
C
Hollow cylinder
D
Ring
3
JEE Main 2021 (Online) 20th July Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
If time (t), velocity (v), and angular momentum (l) are taken as the fundamental units. Then the dimension of mass (m) in terms of t, v and l is :
A
$$[{t^{ - 1}}{v^1}{l^{ - 2}}]$$
B
$$[{t^1}{v^2}{l^{ - 1}}]$$
C
$$[{t^{ - 2}}{v^{ - 1}}{l^1}]$$
D
$$[{t^{ - 1}}{v^{ - 2}}{l^1}]$$
4
JEE Main 2021 (Online) 20th July Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
The correct relation between the degrees of freedom f and the ratio of specific heat $$\gamma$$ is :
A
$$f = {2 \over {\gamma - 1}}$$
B
$$f = {2 \over {\gamma + 1}}$$
C
$$f = {{\gamma + 1} \over 2}$$
D
$$f = {1 \over {\gamma + 1}}$$
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