The Correct Answer is Option (C)
, using this
is independent of mass number.
A is false
1. ⇒ (JEE Main 2023 (Online) 30th January Evening Shift)
Given below are two statements: one is labelled as Assertion and the other is labelled as Reason
Assertion A: The nuclear density of nuclides and can be arranged as
Reason R: The radius of nucleus is related to its mass number as , where is a constant.
In the light of the above statements, choose the correct answer from the options given below
A. and are true and is the correct explanation of
B. Both and are true but is NOT the correct explanation of
C. is false but is true
D. is true but is false
2. ⇒ (JEE Main 2023 (Online) 25th January Morning Shift)
The ratio of the density of oxygen nucleus () and helium nucleus () is
A. 4:1
B. 1:1
C. 2:1
D. 8:1
3. ⇒ (JEE Main 2023 (Online) 11th April Evening Shift)
A nucleus disintegrates into two nuclear parts, in such a way that ratio of their nuclear sizes is . Their respective speed have a ratio of . The value of is __________.
The Crrect Answer is
Let the masses of the two nuclear parts be and , and their respective speeds be and . According to the problem, the ratio of their
nuclear sizes is . Since the nuclear size is proportional to the cube
root of the mass, we can write:
Now, according to the conservation of linear momentum, the momentum before disintegration is
equal to
the momentum after disintegration:
From the problem statement, the ratio of their respective speeds is , so we can write:
Substitute the expression for into the momentum conservation equation:
We know the mass ratio, so substitute that into the equation:
Divide both sides by :
Now, solve for :
Thus, the value of is 2.
4. ⇒ ( JEE Main 2023 (Online) 25th January Evening Shift)
A nucleus disintegrates into two smaller parts, which have their velocities in the ratio 3 : 2. The ratio of their nuclear sizes will be . The value of '' is :-
5. ⇒ (JEE Main 2023 (Online) 24th January Morning Shift)
Assume that protons and neutrons have equal masses. Mass of a nucleon is kg and radius of nucleus is m. The approximate ratio of the nuclear density and water density is . The value of is __________.
6. ⇒(JEE Main 2022 (Online) 26th July Evening Shift)
A nucleus of mass
A. 1 : 2
B. 2 : 1
C. 1 : 1
D. 2 : 3
7. ⇒(JEE Main 2022 (Online) 26th July Evening Shift)
Mass numbers of two nuclei are in the ratio of . Their nuclear densities will be in the ratio of
A. 4 : 3
B.
C. 1 : 1
D.
8. ⇒(JEE Main 2022 (Online) 25th June Evening Shift)
Which of the following figure represents the variation of with (if R = radius of a nucleus and A = its mass number)
A.
B.
C.
D.
9. ⇒(JEE Main 2021 (Online) 25th July Morning Shift)
A particle of mass 4M at rest disintegrates into two particles of mass M and 3M respectively having non zero velocities. The ratio of de-Broglie wavelength of particle of mass M to that of mass 3M will be :
A. 1 : 3
B. 3 : 1
C. 1 :
D. 1 : 1
10. ⇒(JEE Main 2020 (Online) 3rd September Evening Slot)
The radius R of a nucleus of mass number A can be estimated by the formula
R = (1.3
It follows that the mass density of a nucleus is of the order of :
(Mprot.
A. 1024 kg m–3
B. 1010 kg m–3
C. 1017 kg m–3
D. 103 kg m–3
11. The ratio of mass densities of nuclei of 40Ca and 16O is close to :-⇒ (JEE Main 2019 (Online) 8th April Evening Slot)
A. 1
B. 5
C. 0.1
D. 2
The correct answer is option (A)
Densities of nucleus happens to be constant, irrespective of mass number.
12. 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 :⇒ ( JEE Main 2018 (Online) 15th April Evening Slot)
A. 8 : 27
B. 4 : 9
C. 3 : 2
D. 2 : 3
The correct answer is option (C)
The two nuclei have velocity in ratio 8 : 27. By conservation of momentum, we have
Now, since
Therefore,
Thus, ratio of radii of nuclei
13. If radius of the
A.
B.
C.
D.
The correct answer is option (B)
KEY CONCEPT :
Here A = Mass number
14. A nucleus disintegrated into two nuclear parts which have their velocities in the ratio of
A.
B.
C.
D.
The correct answer is option (B)
From conservation of momentum
15. The wavelengths involved in the spectrum of deuterium
A. the size of the two nuclei are different
B. the nuclear forces are different in the two cases
C. the masses of the two nuclei are different
D. the attraction between the electron and the nucleus is different in the two cases
The correct answer is option (C)
The wavelength of spectrum is given by
where mass of electron
mass of nucleus.
For different is different and therefore
is different