1
JEE Main 2021 (Online) 22th July Evening Shift
MCQ (Single Correct Answer)
+4
-1
A nucleus with mass number 184 initially at rest emits an $$\alpha$$-particle. If the Q value of the reaction is 5.5 MeV, calculate the kinetic energy of the $$\alpha$$-particle.
A
5.5 MeV
B
5.0 MeV
C
5.38 MeV
D
0.12 MeV
2
JEE Main 2021 (Online) 22th July Evening Shift
MCQ (Single Correct Answer)
+4
-1
An electron of mass me and a proton of mass mp are accelerated through the same potential difference. The ratio of the de-Broglie wavelength associated with the electron to that with the proton is
A
$${{{m_e}} \over {{m_p}}}$$
B
1
C
$${{{m_p}} \over {{m_e}}}$$
D
$$\sqrt {{{{m_p}} \over {{m_e}}}} $$
3
JEE Main 2021 (Online) 20th July Evening Shift
MCQ (Single Correct Answer)
+4
-1
For a certain radioactive process the graph between In R and t(sec) is obtained as shown in the figure. Then the value of half life for the unknown radioactive material is approximately :
JEE Main 2021 (Online) 20th July Evening Shift Physics - Atoms and Nuclei Question 84 English
A
9.15 sec
B
6.93 sec
C
2.62 sec
D
4.62 sec
4
JEE Main 2021 (Online) 20th July Morning Shift
MCQ (Single Correct Answer)
+4
-1
A radioactive material decays by simultaneous emissions of two particles with half lives of 1400 years and 700 years respectively. What will be the time after which one third of the material remains ? (Take ln 3 = 1.1)
A
740 years
B
1110 years
C
700 years
D
340 years
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