In a nuclear reaction given below, a nucleus X 226 88 changes to another nucleus Y . X 226 88 → Y + α + Energy What is atomic number and mass number of Y ?

Since the given radioactive decay is that of alpha decay as there is an alpha particle emitted, therefore, the equation can be rewritten as, X 226 88 → Y 222 86 + α 2 4 + Energy ∴ Atomic number of Y is 86 Mass number of Y is 222 . Atomic number is the number of protons present in the nucleus of that atom. Mass number is the number of nucleons present in the nucleus of that atom.

How many alpha and beta particles are emitted when uranium nucleus U 238 92 decays to lead Pb 206 82 ?

During α decay, Mass number decrease by 4 and Atomic number decrease by 2 . During β decay, Atomic number increase by 1 . Let x is number of α decays and y is number of β decays. 206 = 238 - 4 x _ _ _ _ _ _ _ ( 1 ) 82 = 92 - 2 x + y _ _ _ _ _ _ _ _ ( 2 ) 4 x = 32 x = 8 Putting value of x in ( 2 ) 82 = 92 - 2 × 8 + y y = 82 + 16 - 92 y = 6 Number of α particle = 8 . Number of β particles = 6 .

If an atom of U 235 , after absorption of a slow neutron undergoes fission to form an atom of Xe 139 and an atom of Sr 94 , what other particles are produced and how many?

The reaction is U 92 235 + n 0 1 → Xe 54 139 + Sr 38 94 + Y . Let Y be the other particles produced which have mass number A . To identify the nature of particles and the number of particles, the sum of atomic number and sum of mass numbers can be compared. The difference between the sum of atomic numbers between reactants and products = ( 92 + 0 ) - ( 54 + 38 ) = 0 . Hence, the particle can be a gamma particle or a neutron. The difference between mass numbers between reactants and products = 235 + 1 - 139 + 94 = 3 . Mass number changes by 3 units. A gamma particle does not have mass value. Hence, the particle should be a neutron. The mass number changes by one unit when a neutron is emitted. So, for a change in mass number 3 , there will be an emission of 3 neutrons.

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When the nucleus that undergoes disintegration during a nuclear disintegration is called a parent nucleus and the nucleus which remains after the disintegration is called daughter nucleus. This law is known as Soddy and Fajan radioactive law.

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Important Questions on Nuclear Physics

MEDIUM

Science>Physics>Nuclear Physics>Alpha, Beta and Gamma Rays and Their Properties

A nucleus

X

captures a

β

particle and then emits a neutron and

γ

ray to form

Y . X

and

Y

are:-

EASY

Science>Physics>Nuclear Physics>Alpha, Beta and Gamma Rays and Their Properties

What is meant by alpha emission ?

HARD

Science>Physics>Nuclear Physics>Alpha, Beta and Gamma Rays and Their Properties

Mass number of a radioactive element is

232

and its atomic number is

90

. When this element undergoes certain nuclear reactions, it transforms into an isotope of lead with a mass number

208

and an atomic number

82

. Determine the number of alpha and beta decay that can occur.

HARD

Science>Physics>Nuclear Physics>Alpha, Beta and Gamma Rays and Their Properties

Which one(s) of the following processes- alpha emission, beta emission, positron emission, electron capture- cause an increase in the atomic number?

EASY

Science>Physics>Nuclear Physics>Alpha, Beta and Gamma Rays and Their Properties

An electric field can deflect:

EASY

Science>Physics>Nuclear Physics>Alpha, Beta and Gamma Rays and Their Properties

What will an alpha particle change into when it absorbs

(i)

one electron

(ii)

two electrons?

MEDIUM

Science>Physics>Nuclear Physics>Alpha, Beta and Gamma Rays and Their Properties

State Soddy and Fajan’s displacement law.

EASY

Science>Physics>Nuclear Physics>Alpha, Beta and Gamma Rays and Their Properties

In a nuclear reaction given below, a nucleus ${}_{88}X^{226}$ changes to another nucleus $Y$ .

${}_{88}X^{226} \to Y + α + Energy$

What is atomic number and mass number of $Y$ ?

HARD

Science>Physics>Nuclear Physics>Alpha, Beta and Gamma Rays and Their Properties

How many alpha and beta particles are emitted when uranium nucleus

{}_{92}U^{238}

decays to lead

{}_{82}{Pb}^{206}

MEDIUM

Science>Physics>Nuclear Physics>Alpha, Beta and Gamma Rays and Their Properties

Which one(s) of the following processes- alpha emission, beta emission, positron emission, electron capture- cause emission of an

X

-ray in every case?

HARD

Science>Physics>Nuclear Physics>Alpha, Beta and Gamma Rays and Their Properties

Which one of the following nuclear transformation is

(np)

type?

HARD

Science>Physics>Nuclear Physics>Alpha, Beta and Gamma Rays and Their Properties

If an atom of

{}^{235}U

, after absorption of a slow neutron undergoes fission to form an atom of

{}^{139}{Xe}

and an atom of

{}^{94}{Sr}

, what other particles are produced and how many?

HARD

Science>Physics>Nuclear Physics>Alpha, Beta and Gamma Rays and Their Properties

Show by equations, the effect on the proton number

Z

and mass number A of the parent nucleus brought about by the two types of radioactive decay.

EASY

Science>Physics>Nuclear Physics>Alpha, Beta and Gamma Rays and Their Properties

For which of the following radiations is the path not affected by electric field and why?

$α$ -rays, $β$ -rays, $γ$ -rays.

EASY

Science>Physics>Nuclear Physics>Alpha, Beta and Gamma Rays and Their Properties

Can a radioactive substance emit both

α

and

β

rays simultaneously?

MEDIUM

Science>Physics>Nuclear Physics>Alpha, Beta and Gamma Rays and Their Properties

The isotope of

{}_{92}U^{238}

decays by alpha emission to an isotope of thorium

(Th)

. The thorium isotope decays by beta emission to an isotope of protactinium

(Pa)

. Write down the equation to represent these two nuclear changes.

MEDIUM

Science>Physics>Nuclear Physics>Alpha, Beta and Gamma Rays and Their Properties

Which one(s) of the following processes- alpha emission, beta emission, positron emission, electron capture- cause a decrease in the atomic number?

MEDIUM

Science>Physics>Nuclear Physics>Alpha, Beta and Gamma Rays and Their Properties

Give scientific explanation:

When the radiation coming out from certain radioactive substance is passed through an electric field, marks are found at three places on the photographic plate placed in its path.

EASY

Science>Physics>Nuclear Physics>Alpha, Beta and Gamma Rays and Their Properties

How many alpha and beta particles are emitted when Uranium nucleus

_{92} U^{238}

decays to lead

_{82} U^{206}

EASY

Science>Physics>Nuclear Physics>Alpha, Beta and Gamma Rays and Their Properties

A radioactive element

{}_{Z}X^{A}

first emits two

β

particles and then an alpha particle and the resulting nucleus can be represented by

{}_{Q}Y^{P}

. What are the values of

P

and

Q

in terms of

A

and

Z

When the nucleus that undergoes disintegration during a nuclear disintegration is called a parent nucleus and the nucleus which remains after the disintegration is called daughter nucleus. This law is known as Soddy and Fajan radioactive law.

Important Questions on Nuclear Physics

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