1
JEE Main 2018 (Online) 15th April Evening Slot
+4
-1
An unstable heavy nucleus at rest breaks into two nuclei which move away with velocities in the ratio of 8 : 27. The ratio of the radii of the nuclei (assumed to be spherical) is :
A
8 : 27
B
4 : 9
C
3 : 2
D
2 : 3
2
JEE Main 2018 (Online) 15th April Evening Slot
+4
-1
Muon ($$\mu$$$$-$$) is a negatively charged (|q| = |e|) particle with a mass m$$\mu$$ = 200 me, where me is the mass of the electron and e is the electronic charge. If $$\mu$$$$-$$ is bond to a proton to form a hydrogen like atom, identify the correct statements.
(A)   Radis of the muonic orbit is 200 times smaller than that of the electron.
(B)   The speed of the $$\mu$$$$-$$ in the nth orbit is $${1 \over {200}}$$ times that of the electron in the nth orbit.
(C)   The ionization energy of muonic atom is 200 timesmore than of an hydroen atom.
(D)   The momentum of the muon in the nth orbit is 200 times more than that of the electron.
A
(A),    (B),    (D)
B
(A),    (C),    (D)
C
(B),    (D)
D
(C),    (D)
3
JEE Main 2018 (Online) 15th April Morning Slot
+4
-1
The energy required to remove the electron from a singly ionized Helium atom is $$2.2$$ times the energies required to remove an electron from Helium atom. The total energy required to ionize the Helium atom completely is :
A
$$20$$ $$eV$$
B
$$34$$ $$eV$$
C
$$79$$ $$eV$$
D
$$109$$ $$eV$$
4
JEE Main 2018 (Online) 15th April Morning Slot
+4
-1
A solution containing active cobalt $${{60} \over {27}}Co$$ having activity of $$0.8$$ $$\mu Ci$$ and decay constant $$\lambda$$ is injected in an animal's body. If $$1\,c{m^3}$$ of blood is drawn from the animal's body after $$10$$ hrs of injection, the activity found was $$300$$ decays per minute What is the volume of blood that is flowing in the body ? $$\left( {\,\,Ci = 3.7 \times {{10}^{10}}\,} \right.$$ decays per second and at $$t=10$$ hrs $$\left. {{e^{ - \lambda t}} = 0.84} \right)$$
A
$$6$$ liters
B
$$7$$ liters
C
$$4$$ liters
D
$$5$$ liters
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Mechanics
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Modern Physics
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