1
WB JEE 2021
MCQ (Single Correct Answer)
+1
-0.25
Let r, v, E be the radius of orbit, speed of electron and total energy of electron respectively in H-atom. Which of the following quantities according to Bohr theory, is proportional to the quantum number n ?
A
vr
B
rE
C
$${r \over E}$$
D
$${r \over v}$$
2
WB JEE 2020
MCQ (Single Correct Answer)
+1
-0.25
If R is the Rydberg constant in cm-1, then hydrogen atom does not emit any radiation of wavelength in the range of
A
$${1 \over R}$$ to $${4 \over {3R}}$$ cm
B
$${7 \over 5R}$$ to $${19 \over {5R}}$$ cm
C
$${4 \over R}$$ to $${36 \over {5R}}$$ cm
D
$${9 \over R}$$ to $${144 \over {7R}}$$ cm
3
WB JEE 2020
MCQ (Single Correct Answer)
+1
-0.25
A nucleus X emits a $$\beta $$-particle to produce a nucleus Y. If their atomic masses are Mx and My respectively, then the maximum energy of the $$\beta $$-particle emitted is (where, me is the mass of an electron and c is the velocity of light)
A
$$({M_x} - {M_y} - {m_e}){c^2}$$
B
$$({M_x} - {M_y} + {m_e}){c^2}$$
C
$$({M_x} - {M_y} ){c^2}$$
D
$$({M_x} - {M_y} - {2m_e}){c^2}$$
4
WB JEE 2020
MCQ (Single Correct Answer)
+1
-0.25
For nuclei with mass number close to 119 and 238, the binding energies per nucleon are approximately 7.6 MeV and 8.6 MeV, respectively. If a nucleus of mass number 238 breaks into two nuclei of nearly equal masses, what will be the approximate amount of energy released in the process of fission?
A
214 MeV
B
119 MeV
C
2047 MeV
D
1142 MeV
WB JEE Subjects