Atoms and Nuclei · Physics · TS EAMCET
MCQ (Single Correct Answer)
The maximum wavelength of incident radiation required to ionize a hydrogen atom in its ground state is nearly
When an element ${ }_{90}^{232} \mathrm{Th}$ decays into ${ }_{82}^{208} \mathrm{~Pb}$, the number of $\alpha$ and $\beta^{-}$particles emitted respectively are
During the disintegration of a radioactive nucleus of mass number 208 at rest, two alpha particles each with kinetic energy $E$ are emitted. The total kinetic energy of the emitted alpha particles and the daughter nucleus after the disintegration is
If the total energy of an electron in an orbit is positive, then
If $87.5 \%$ of atoms of a radioactive element decay in 6 days, then the fraction of atoms of the element that decay in 8 days is
If the ratio of the mass numbers of two nuclei is $27: 125$, then the ratio of their surface areas is
The range of weak nuclear force is of the order of
The potential energy of an electron in an orbit of hydrogen atom is -6.8 eV . The de-Broglie wavelength of the electron in this orbit is
( $r_o$ is Bohr radius)
If a radioactive substance decays $10 \%$ in every 16 hours, then the percentage of the radioactive substance that remains after 2 days is
If a nucleus $P$ converts into a nucleus $Q$ by the decay of one alpha particle and two $\beta^{-}$particles, then the nuclei $P$ and $Q$ are
The phenomenon of physics that deals with the constitution and structure of matter at the minute scales of atoms and nuclei is
The ratio of wavelengths of second line in Balmer series and the first line in Lyman series of hydrogen atom is
A radioactive material of half-life 2.5 hours emits radiation that is 32 times the safe maximum level. The time (in hours) after which the material can be handled safely is
If the number of uranium nuclei required per hour to produce a power of 64 kW is $7.2 \times 10^{18}$, then the energy released per fission is
Bose-Einstein statistics is applicable to particles with
The ratio of the kinetic energies of the electrons in the third and fourth excited states of hydrogen atom is
In $\beta^{-}$decay, a neutron transforms into a proton within the nucleus according to the equation :
neutron $\rightarrow$ proton $+\beta^{-}+x$
In this equation the particle represented by ' $x$ ' is
Two radioactive substances $A$ and $B$ have same number of initial nuclei. If the half lives of $A$ and $B$ are 1.5 days and 4.5 days respectively, then the ratio of the number of nuclei remaining in $A$ and $B$ after 9 days is
If the difference in the frequencies of the first and second lines of Lyman series of hydrogen atom is $f$, then the difference in frequencies of the first and second lines of Balmer series of hydrogen atom is
The average energy of a neutron produced in the fission of ${ }_{92}^{235} \mathrm{U}$ is
If $96.875 \%$ of a radioactive substance decays in 10 days, then the half life of the substance is (in days)
Match the following.
(Take the relative strength of the strongest fundamental forces in nature as one)
| List-I (Fundamental forces in nature) |
List-II (Relative strength) |
||
|---|---|---|---|
| (A) | Strong nuclear force | (e) | $10^{-2}$ |
| (B) | Weak nuclear force | (f) | 1 |
| (C) | Electromagnetic force | (g) | $10^{10}$ |
| (D) | Gravitational force | (h) | $10^{-13}$ |
| (i) | $10^{-39}$ | ||
Energy released in the fission of a single uranium nucleus is 200 MeV . Then the number of fissions per second to produce 5 mW power is
The ratio of longest wavelengths of the spectral lines in the Lyman and Balmer series of hydrogen spectrum is
Half-life of a radioactive substance $A$ is two times the half-life of another radioactive substance $B$. Initially the number of nuclei of $A$ and $B$ are $N_A$ and $N_B$ respectively. After three half-lives of $A$, the number of nuclei of both are equal. Then $N_A / N_B$ is
The ratio of the relative strengths of strong and weak nuclear forces is
In a hypothetical Bohr hydrogen atom, if the mass of the electron is doubled then the energy of the electron in the first orbit is
The half-life period of element $X$ is same as the mean life time of element $Y$. Assume initially $X$ and $Y$ have same number of atoms. Then
Heavy water is used as moderator in nuclear reactor because
The radius of a nucleus of mass number 27 is $R$. Which of the following is true about a nucleus whose radius is $2 R$ ?
The nucleus ${ }_{50}^{120} X$ undergoes the series of reactions given below:
$$ { }_Z^A X \xrightarrow{\alpha \text {-decay }} P \xrightarrow{\beta^{-} \text {-decay }} Q \xrightarrow{\alpha \text {-decay }} R $$
The number of neutrons in the nucleus $R$ is
In hydrogen spectrum, the shortest and longest wavelengths of Balmer series are $\lambda_1$ and $\lambda_2$ respectively. The Rydberg constant of hydrogen is
$\alpha$-decay of a parent nucleus $X$ results in a daughter nucleus $Y$. If $m_x, m_y$ and $m_\alpha$ are the masses of the parent nucleus, the daughter nucleus and the $\alpha$-particles respectively, then the net kinetic energy gained in the process is
In the nuclear fission of one nucleus of $\mathrm{U}^{235}$ the energy released is 188 MeV . The energy released in the nuclear fission of 235 g of $\mathrm{U}^{235}$ is nearly
(Avogadro number $=6.02 \times 10^{23} \mathrm{~mol}^{-1}$ )
If $F_1$ and $F_2$ are the relative strengths of the gravitational and weak nuclear forces respectively, then $F_2 / F_1$ is nearly
In the following nuclear reaction $X$ is
$$ { }_{13} \mathrm{Al}^{27}+{ }_2 \mathrm{He}^4 \longrightarrow{ }_0 n^1+X $$
Among the fundamental forces, which one of the following is the strongest force?
The shortest wavelength in Balmer series of hydrogen atom spectrum is approximately equal to (use $R_H=1.097 \times 10^7 \mathrm{~m}^{-1}$ )
What will be the energy released in joule, in the process of fission by 1 mg of ${ }_{92}^{240} \mathrm{U}$. Assume energy release per fission is 200 MeV .
[use Avogadro's number as $6 \times 10^{23}$ and 1 eV $=1.6 \times 10^{-19} \mathrm{~J}$ ]
Which of the following statements is true?
The energy of an electron in the fourth excited state of the hydrogen atom is
Estimate the approximate volume of aluminium nucleus $(A=27)$, use $\binom{R_0 \simeq 1.0 \times 10^{-15} \mathrm{~m}}{\pi \simeq 3}$
The range of the nuclear force is
Considering the Bohr's model of hydrogen atom, the ratio of velocities of electrons orbiting in the 4th orbit to that in the 9 th orbit is
What is the mass number of the nucleus having radius equal to $\frac{1}{3}$ of that of ${ }^{189} \mathrm{Os}$ ?
The difference in the wavelength between the maximum and minimum of Balmer series (use $R_H=1 \times 10^7 \mathrm{~m}^{-1}$ )
The radius and mass number of nucleus 1 is $R_1$ and $A_1$, respectively. The radius and mass number of nucleus 2 is $R_2$ and $A_2$, respectively. If $A_2$ is larger than $A_1$ by $2 \%$, then $R_2$ is larger than $R_1$ by
Which of the following interaction is responsible for beta decay?
If the series limit frequency of Balmer series is $v_B$, then the series limit frequency of the Brackett series is
Consider a nucleus ${ }_{30}^{60} \mathrm{X}$. Its approximate density is (take, $1 \mathrm{amu}=1.6 \times 10^{-27} \mathrm{~kg}, R_0=1.2 \times 10^{-15} \mathrm{~m}$ )
As the mass number $A$ increases, which of the following quantities related to a nucleus does not change?
If the first line in the Lyman series has wavelength $\lambda$, then the first line in Balmer series has the wavelength
The half-life of a radiocative isotope is 30 h . How long will it take to get reduced to $12.5 \%$ of its initial amount?
Half-life of radioactive sample is 24 h . If a newly prepared radioactive sample shows 4 times the allowed and safe value of radio activity, the minimum time after which one can work safely with the source is
The binding energy (BE) per nucleon for an element is 7.14 MeV . If the BE of element is 28.6 MeV , then the number of nucleons in the element is
Let $G, W, E$ and $S$ be relative strength of gravitational, weak-nuclear, electromagnetic and strong-nuclear forces, respectively. Which of the correct statement?
In the Bohr model an electron of mass $m$ moves in a circular orbit around the proton. Considering the orbiting electron to be a circular current loop, the magnetic moment of the hydrogen atom, when the electron is in $n$th excited state. (Assume, $h=$ Planck's constant)
A radioactive element which can decay by two processes, has half-life $t_1$ for first process and half-life $t_2$ for second process. Let $\langle t\rangle$ be the effective average-life of this element. Which of the following is correct?
In atomic scale the weakest force in nature is
The wavelength of a spectral line emitted by hydrogen atom in the Balmer series is $\frac{16}{3 R}$
( $R$ is Rydberg constant). What is the value of the principal quantum number of the state from which the transition takes place?
The half-life of a radioactive sample is 5 s . If the initial mass of the sample is 60 g , then the time required to reduce the sample to 7.5 g is
The nuclear forces are
The ratio of maximum to minimum wavelength in Balmer series of an hydrogenic atom is
Alpha rays emitted from a radioactive substance are