1
JEE Main 2021 (Online) 20th July Morning Shift
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Change Language
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
2
JEE Main 2021 (Online) 20th July Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
A nucleus of mass M emits $$\gamma$$ -ray photon of frequency 'v'. The loss of internal energy by the nucleus is :

[Take 'c' as the speed of electromagnetic wave]
A
hv
B
$$hv\left[ {1 + {{hv} \over {2M{c^2}}}} \right]$$
C
$$hv\left[ {1 - {{hv} \over {2M{c^2}}}} \right]$$
D
0
3
JEE Main 2021 (Online) 18th March Evening Shift
MCQ (Single Correct Answer)
+4
-1
Out of Syllabus
Change Language
The decay of a proton to neutron is :
A
always possible as it is associated only with $$\beta$$+ decay
B
possible only inside the nucleus
C
not possible as proton mass is less than the neutron mass
D
not possible but neutron to proton conversation is possible
4
JEE Main 2021 (Online) 18th March Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Imagine that the electron in a hydrogen atom is replaced by a muon ($$\mu$$). The mass of muon particle is 207 times that of an electron and charge is equal to the charge of an electron. The ionization potential of this hydrogen atom will be :
A
13.6 eV
B
2815.2 eV
C
331.2 eV
D
27.2 eV
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