Goyal Brothers Prakashan solutions for अ न्यू अप्रोच टू आईसीएसई [अंग्रेजी] कक्षा १० chapter 11 - Radioactivity [Latest edition]

What do you understand by the term radioactivity?

Name two radioactive substances.

Which part of an atom is involved during radioactive emission?

Diagram alongside shows a lead cube containing radioactive substance ‘R’. A magnetic field is applied, perpendicular to the path of nuclear radiation by a powerful horse-shoe magnet, P and Q beings its poles. The nuclear radiations split into three distinct parts X, Y and Z.

(a) (i) Identify X and state its mass and charge.

(ii) Identify Y and state its nature.

(iii) Identify Z and state its mass and charge.

(b) Identify the magnetic polarity of (i) P and (ii) Q.

(c) Which law helped you to find the polarity of the magnet? State the law.

1. What do you understand by the term 𝛼-particles as applied to radioactivity?
2. Why are these particles called helium nuclei?

Answer the following question about α-particles.

What is its mass number and electric charge in a.m.u.?

Answer the following question about α-particles.

How many times is it more ionising than γ-radiations?

Answer the following question about α-particles.

How many times is it less penetrating than β-particles?

Answer the following question about α-particles.

What is the range of penetration in air?

During alpha emission of a radioactive element, how do the following change?

1. Atomic number of the radioactive element.
2. Mass number of the radioactive element.

Why are γ-radiations emitted during α-emission?

How do the chemical properties of new element compare with the original element, after the emission of alpha particle?

Answer the following question about γ-emission:

From which part of an atom this emission is given out?

Answer the following question about γ-emission:

What is its range of penetration in air?

Answer the following question about γ-emission:

What is the effect of an electric or magnetic field on this radiation?

Answer the following question about γ-emission:

Why are these radiations considered harmful?

Answer the following question about γ-emission:

State one particular use of this radiation.

Answer the following question about β-radiation.

Is it a radiation or a particle?

Answer the following question about β-radiation.

What is its mass in a.m.u.?

Answer the following question about β-radiation.

What is its charge in coulombs?

Answer the following question about β-radiation.

From which part of an atom it is emitted?

Answer the following question about β-radiation.

Is there any difference between electrons and β-particles?

An element \[{ }_{\mathrm{z}} \mathrm{X}^{\mathrm{A}}\] decays to \({ }_{88} \mathrm{Y}^{222}\) after emitting two alpha particles and one beta particle. What are the values of atomic mass A and atomic number Z in element X?

A radioactive substance is oxidized. Will there be any change in the nature its radioactivity? Give a reason for your answer

Represent the change in the nucleus of a radioactive element when a β particle is emitted.

What is the name given to elements with the same mass number and different atomic number?

Under which conditions does the nucleus of an atom tend to radioactive?

Arrange the α, β and γ radiations in ascending order of their penetrating power.

Arrange alpha (α), beta (β) and gamma (γ) radiation in the:

Descending order of ionising power.

Arrange the α, β, and γ radiation in ascending order of their biological damage. Give reason.

1. Name the radiation that is emitted during the decay of a nucleus that has the highest penetrating power.
2. Does the emission of the above-mentioned radiation result in a change in the mass number?

(a) \({ }_{92} \mathrm{X}^{238} \xrightarrow{-\beta} \mathrm{X}_{1}^{-} \xrightarrow{-\alpha} \mathrm{X}_{2}^{-} \xrightarrow{-\alpha} \mathrm{X}_{3}^{-} \xrightarrow{-\beta} \mathrm{X}_{4}^{-} \xrightarrow{-\alpha} \mathrm{X}_{5}^{-} \xrightarrow{-\alpha} \mathrm{X}_{6}^{-}\)

Study the decay of \({ }_{92} \mathrm{X}^{238}\) carefully and complete the chain of mutations by writing the mass number and atomic number from X₁ to X₆.

(b) From the above transformations, identify.

1. Isotopes
2. Isobars

State giving reasons, whether the following nuclear mutation is possible or not. (Star indicates an excited state)

\({ }_{\mathrm{Z}} \mathrm{X}^{* \mathrm{~A}} \longrightarrow{ }_{\mathrm{Z}} \mathrm{X}^{\mathrm{A}}+\mathrm{Y}\)

State giving reasons, whether the following nuclear mutation is possible or not. (Star indicates an excited state)

\({ }_{\mathrm{Z}} \mathrm{X}^{\mathrm{A}} \longrightarrow{ }_{\mathrm{Z}-2} \mathrm{X}_{1}{ }^{\mathrm{A}-4}+{ }_{2} \mathrm{He}^{4}\)

An atomic nucleus A is composed of 84 protons and 128 neutrons.

1. The nucleus A emits a beta particle and is transformed into nucleus B. What is the composition of nucleus of B?
2. The nucleus B emits an α-particle and is transformed into nucleus C. What is the composition of nucleus C?
3. Does the composition of nucleus C change if it emits a γ-radiation?

A nucleus `""_11^24Na`  emits a beta particle to change into Magnesium (Mg).

1. Write the symbolic equation for the process.
2. What are numbers 24 and 11 called?
3. What is the general name of `""_12^24Mg `with respect to `""_11^24Na`?

The graph illustrates the correlation between the number of protons (x-axis) and the number of neutrons (y-axis) for elements A, B, C, D, and E in the periodic table. These elements are denoted by the letters rather than their conventional symbols.

1. Identify the radioactive radiation emitted when element C decays into element E. Represent this using a nuclear reaction.  (1)
2. What is the special name given to elements D and E?  (1)
3. If element C transforms into element B by emitting a radioactive ray, how will this ray behave in an electric field?  (2)

Define nuclear fission.

Name two radioactive materials which are commonly used in nuclear reactors.

Why is the energy produced by nuclear reactors considered as hazard?

Complete the following nuclear equation.

\[\ {}_{11}\mathrm{Na}^{24} \xrightarrow{- \beta} {}_{\ldots\ldots}\mathrm{Mg}^{\ldots\ldots} \]

Complete the following nuclear equation.

\[ \ {}_{92}\mathrm{U}^{235} + {}_{0}\mathrm{n}^{1} \longrightarrow {}_{\ldots\ldots}\mathrm{Ba}^{141} + {}_{36}\mathrm{Kr}^{\ldots\ldots} + 3 \ {}_{0}\mathrm{n}^{1} + \text{Energy} \]

Complete the following nuclear equation.

\[ \ {}_{92}\mathrm{U}^{236} \longrightarrow {}_{51}\mathrm{Sb}^{\ldots\ldots} + {}_{\ldots\ldots}\mathrm{Nb}^{99} + 4 \ {}_{0}\mathrm{n}^{1} + \text{Energy} \]

Define nuclear fusion.

Why nuclear fusion is not possible for commercial purposes?

Name two places in the universe where nuclear fusion takes place.

Complete the following nuclear fusion equation:

\[\ {}_{1}\mathrm{H}^{2} + {}_{1}\mathrm{H}^{2} \longrightarrow {}_{\ldots\ldots}\mathrm{H}^{\ldots\ldots} + {}_{1}\mathrm{H}^{1} + \text{Energy}\]

Complete the following nuclear fusion equation:

\[ \ {}_{1}\mathrm{H}^{3} + {}_{1}\mathrm{H}^{2} \longrightarrow {}_{\ldots\ldots}\mathrm{He}^{\ldots\ldots} + {}_{0}\mathrm{n}^{\ldots\ldots} + \text{Energy} \]

The atoms of same element having same atomic number, but different atomic masses are called:

When an element gives out high energy radiations on its own, the change which takes place is:

The atoms of different elements having the same mass number, but different atomic numbers are called:

The radiations given out by radioactive elements:

A radioactive substance emits:

During α-emission:

A nucleus of an atom consists of 146 neutrons and 95 protons. It decays after emitting an alpha particle. How many protons and neutrons are left in the nucleus after an alpha emission?

During β-emission an electron is ejected from the atom of radioactive substance. The electron is ejected from:

Which of the following radiation is most ionising?

Which of the following radiation is most penetrating?

Which of the following radiation gets deflected most in electric or magnetic field?

Atoms of different elements having the same number of neutrons, but different atomic numbers are called:

Which is a pair of isotones?

Which is a pair of isobars?

Which one is/are pair of isotopes?

Which one of the following has least ionising power?

Which one of the following has least penetrating power?

Which one is not deflected by electric or magnetic fields?

An alpha particle gains two electrons. In doing so, it changes to:

A beam of alpha particles is subjected to a strong magnetic field. The alpha particles are:

A beam of beta particles is subjected to a strong magnetic field. The beta particles are:

Nuclear radiations are consisting of alpha, beta and γ-radiation is subjected to strong magnetic field:

\({ }_{11} \mathrm{Na}^{24} \longrightarrow{ }_{\mathrm{Q}} \mathrm{Mg}^{\mathrm{P}}+{ }_{-1} \mathrm{e}^{0}\)

In the above equation, the values of P and Q are:

\[ {}_{86}\mathrm{Rn}^{222} \longrightarrow {}_{\mathrm{y}}\mathrm{Po}^{\mathrm{x}} + {}^{\phantom{+}4}_{+2}\mathrm{He} \]

In the above equation, the values of x and y are:

During beta emission:

\({ }_{92} \mathrm{U}^{236} \longrightarrow{ }_{56} \mathrm{Ba}^{\mathrm{x}}+{ }_{y}\mathrm{~K} r^{92}+3{ }_{0} \mathrm{n}^{1} + \text{energy}\)

In the above nuclear equation, the values of x and y are:

When the nucleus of a radioactive element, such as uranium is hit by a slow moving neutron, such that it splits into two almost equal nuclei with the release of more neutrons and energy, then the process is called:

The reaction which takes place in nuclear reactors is:

When two lighter nuclei fuse to form a heavier nucleus with the release of enormous energy, under pressure and temperature of more than million degrees celsius, the process is called:

Nuclear fusion is not possible in the laboratory because:

Assertion (A): If an atom undergoes a chemical change occurring at a low energy, there is a change in the number of orbital electrons of the atom.

Reason (R): If the atom undergoes a nuclear change which occurs at a high energy, there is a change in the number of nucleons inside the nucleus of the atom.

Assertion (A): The beta particle resides inside the nucleus of atom in the form of electron.

Reason (R): Inside the nucleus, the change of a neutron into a proton and an elecron causes the emission of a β-particle \[ \left( {}^{1}_{0}n \longrightarrow {}^{1}_{1}p + {}^{\phantom{-}0}_{-1}e \right) \].

Assertion (A): X-rays are emitted when there is transition of electrons in the inner orbits of an atom.

Reason (R): Gama radiations are given out from the nucleus.

Assertion (A): Alpha and beta particles are deflected in an electric or a magnetic field, but gamma rays are not deflected in such a field.

Reason (R): Alpha and beta particles are charged but gamma rays are uncharged.

Assertion (A): The isotope \[ {}^{235}_{\phantom{1}92}\mathrm{U} \] is more easily fissionable than the isotope \[ {}^{238}_{\phantom{1}92}\mathrm{U} \].

Reason (R): The fission of \[ {}^{238}_{\phantom{1}92}\mathrm{U} \] nucleus is possible even by slow neutrons, while the fission of the \[ {}^{235}_{\phantom{1}92}\mathrm{U} \] nucleus can occur only by fast neutrons.

The reaction responsible for the production of energy in the sun is ______.

Gamma radiations are highly penetrating radiation which can pass through 30 cm of ______.

When an element ejects a beta particle, a neutron in the nucleus decays to ______ and β-particle.

The radioactive radiations which are not electrically charged, travel at the speed of ______.

Man has been able to produced ______ reaction in the form of hydrogen bomb.

Match the statements in Column A with those in Column B.

Which of the following equations are correctly balanced?

A. \({ }_{p-5}^{q-1} X \longrightarrow{ }_{p-3}^{q-5} Y+{ }_{2}^{4} \mathrm{He}\)

B. \[\ {}^{q - 4}_{p - 4}Z \longrightarrow {}^{q - 4}_{p - 5}X + {}^{\phantom{-}0}_{-1}e \]

C. \({ }_{p-5}^{q-1} \mathrm{X} \longrightarrow{ }_{p-7}^{q-5} \mathrm{Y}+{ }_{2}^{4} \mathrm{He}\)

D. \[ {}^{q - 4}_{p - 7}Z \longrightarrow {}^{q - 4}_{p - 5}X + 2 \ {}^{\phantom{-}0}_{-1}e \]

Which of the following combinations correctly shows the charges on the particles?

The graph illustrates the correlation between the number of protons (x-axis) and the number of neutrons (y-axis) for element C in the periodic table. The element is denoted by letters rather than their conventional symbols. When element C, depicted in the graph, undergoes radioactive decay, it releases radioactive rays.

(a) Write the chemical symbol along with the mass number and atomic number for the element denoted as 'C'.

(b) Plot on the graph,

1. The daughter element after the emission of beta radiation by the element 'C'.
2. The daughter element, as indicated in the previous answer, if it undergoes alpha decay.

An element $$_{Z}P^{A}$$ emits one α-particle and then two β-particles consecutively to form an element Q.

1. Show all the transformations by means of equations only.
2. What are P and Q called?