Radioacticity

Question 1

electron negative charge equals

Answer 1

-1.6 * 10 ^-19 C

Question 2

Electron mass

Answer 2

9.1 * 10^-31 Kg

Question 3

electron mass is

Answer 3

1/ 1840 times mass of a proton

Question 4

what is mean by atomic number ?

what mass of proton ?

Answer 4

The total number of Proton in the nucleus determines the place of atom in periodic table its known as Atomic number
Atomic number denoted by z
1.6726* 10^-27 Kg

Question 5

Say about neutron

Answer 5

Electrically neutral

is mass equals to 1.6749 * 10^-27 kg

Question 6

What is mass number ?

what is mass of mass of nucleus ?

Answer 6

Total number of nucleons in the nucleus .
Nucleons means Sum of proton + neutron

Mass of Nucleus is equal to Mass of proton multiplied by mass number
mass of proton [ 1.67 * 10^-27 kg ]

Question 7

If an atom undergoes chemical change at low energy what happens ?
if an atom undergoes Nuclear change at high energy what happens ?

Answer 7

there is a change in number of orbital structure

there is a change in number of nucleons inside the nucleus

Question 8

Isotopes means

Answer 8

the atom of the same element , having same atomic number , but different mass number are called isotopes

Question 9

Hydrogen isotopes

Answer 9

Protium , Deuterium , Tritium

Question 10

Isobars means

Answer 10

Atoms of different element which have same mass number but different atomic number

Question 11

if the number of neutrons and protons gets interchanged inside the nucleus what does it means ?

Answer 11

mirror Isobar

Question 12

Isotones means

Answer 12

Atoms having different number of Atomic and mass number but has same neutrons its known as Isotones

Question 13

Radioactivity -
Who discovered ?
How?

Answer 13

Henry Becquerel Discovered the phenomenon of radio activity in 1896
In a dark room with uranium salt and photographic plate
He named the radiations as Becquerel rays

Question 14

The three radiations

Answer 14

Alpha - +
Beta - -
Gamma- neutral

Question 15

Radioactive substance means

Answer 15

Substance which disintegrate by the spontaneous emission of radiations are called radioactive substance

Question 16

Natural radioactive substances

Answer 16

The atoms which has number of neutrons much more than number of protons
is called natural radioactive substance

Question 17

Radioactivity is a natural phenomenon why ?

Answer 17

any physical change or chemical change cannot affect the nature of radiation emitted by a substance and its rate of decay
this clearly shows the Phenomenon of radioactivity is not by Outer electron which can be easily affected rather its by property of nucleus

Question 18

The three rays and Rutherford experiment explain it

Answer 18

Alpha , Beta , Gamma
Rutherford experiment says the rays which turns left are Alpha
The rays which turns Right are Beta
the rays which goes undeviated are Gamma

Question 19

About Gamma radiations

Answer 19

Gamma radiations are electromagnetic waves similar to light waves and therefore not affected by magnetic field

Question 20

If we have made this experiment by keeping Electric plate in perpendicular to their part what will happen ?

Answer 20

The rays which move towards positive path are Beta
rays moving towards negative path are Alpha
Undeviated straight waves are Gamma

Question 21

Properties of Alpha waves

Mass and charge of Alpha atom

Answer 21

• The mass of Alpha atom is roughly 4 times the mass of proton
  and its charge is twice the charge of proton
  mass of Alpha atom = 6.68 * 10^-27 kg
  Charge of Alpha atom = + 3.2 * 10 ^-19 C
  Specific Charge = 4.79 * 10 ^ 7 C kg ^-1

Question 22

Properties of Alpha particles

Alpha particle consists of

Answer 22

Two protons and Two neurons
It is same as doubly ionised helium atom

If alpha particles gains one electron it changes to singly ionised helium atom
if it gains two electron it changes into helium atom

Question 23

Properties of Alpha particle

Speed of Alpha particle

Answer 23

10^7 ms ^-1
All the alpha particle emitted from the nucleus of the same radioactive substance don’t have same energy , but they have energy distributed in a small range

Question 24

Properties of Alpha particle

Alpha particle ionises

Answer 24

An alpha particle strongly ionises the gas through which it passes
Ionising Power of Alpha particle is roughly 100 times that of beta particle and roughly 10,000 times that of Gamma radiations

Question 25

Properties of Alpha | On basis of energy

Answer 25

Alpha particle dissipates its energy as it moves through a medium and therefore its penetrating power is quite small It can penetrate through 3 to 8 cm in air It can easily stopped by thin card sheet or thick paper Its penetrating power is 1/100 times of beta particle and 1/ 10000 of gamma particle

Question 26

Properties of Alpha particle | On basis of Charge

Answer 26

Alpha particles are Positively charged , so they are deflected by the electric and magnetic field deflection of Alpha particle is less as compared to Beta particles because Alpha particle has more mass than beta particle

Question 27

Properties of Alpha particles | On basis of Photographic plate

Answer 27

Alpha particles affect photographic plate

Question 28

Properties of Alpha particles | On basis of fluorescence

Answer 28

Alpha particle cause fluorescence on striking a fluorescent material

Question 29

Properties of Alpha particles | on basis of kinetic energy

Answer 29

Alpha particles have Large kinetic energy and momentum with them They used to bombard the nucleus of an atom of one element to convert it into another element

Question 30

Properties of Alpha particles | Destruction and scatter

Answer 30

Destroy living cells and also causes biological damage | Alpha particles scatter while passing through the thin mica

Question 31

Properties of Beta particles | Affection of Photographic plate , fluorescence , production ,biological damage

Answer 31

Affect photographic plate causes fluorescence on striking fluorescent material produce x rays when they are stopped by the metals [ such as tungsten ] of high atomic number and high melting point Causes more biological damage than alpha particles as they can easily pass through skin of our body

Question 32

``` Properties of Beta particles Mass and charge of beta particles their origin what is Beta particle Speed of Beta particle ```

Answer 32

Mass = 9.1 * 10^-31 kg charge = -1.6 * 10^-19 C Specific charge = 1.76 * 10^11C kg ^-1 Although both Beta and cathode rays are fast moving electron , they differ in their origin . Beta particles are given out from their nucleus of the atom , while cathode rays are given out by orbital electron Beta particles are the fast moving electron emitted from the nucleus Speed of Beta particles is of the order of 10^8 ms^-1 , different beta particles emitted from different radioactive substances as different speed

Question 33

Properties of Beta particles IOnisation penetrating power Charge

Answer 33

Beta particles ionise the gas through which they pass , Ionising power of beta particle roughly 1 / 100th times that of the alpha particles , but nearly 100 times that of gamma radiation Penetrating power of beta particle is more than that of alpha particles but less than that of gamma particles they can travel through 5m in air and pass through thin cardboard sheet , even through thin aluminium foil but 5mm aluminium sheet can stop beta particle Beta particle are negatively charged , so they get deflected by the electric and magnetic field deflection of beta is more than that of Alpha as beta is thinner than Alpha

Question 34

``` Properties of Gamma What is gamma ray ? speed of gamma ray ? Ioinsing power of gamma? penetrating power of gamma? ```

Answer 34

Gamma radiations are electromagnetic waves like x-rays and light , but they differ from x rays and light in wavelength wavelength of Gamma rays are 10 ^-4 nm Speed of Gamma radiation is same as Speed of light Ionising power is very low for gamma ray Penetrating power of gamma ray is very high A thick sheet of lead is required to stop it

Question 35

``` Properties of gamma Gamma rays are like affect photographic plate ? Causes fluorescence ? diffracted by ? used for? can easily pass through ? ```

Answer 35

Gamma rays are like x rays , light , since they are not charged they are not deflected by any magnetic and electric field They affect photographic plate Causes fluorescence when they strike fluorescent material diffracted by crystals like x rays used for treating cancer easily pass through human body can make immense damage

Question 36

Although X rays and Gamma rays are similar property | Their origin is different

Answer 36

X rays are emitted when there is transition of electron in inner orbits of atom , whereas gamma radiation are given out from nucleus