radiation powerpoint (pysics 10) dog a s fgdgdfffffffffg

8/13/2019 Radiation Powerpoint (pysics 10) dog a s fgdgdfffffffffg

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Radiationis energy in transit in the form of high speed particles

and electromagnetic waves as seen in diagram.

There are basically 2 types of radiation: the ionizing radiation

and the non-ionizing radiation.


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The electromagnetic waves that we often encounter such

as visible light, radio waves, infrared, microwaves and UV are

electromagnetic waves that do not carry enough energy to

separate molecules or remove electrons from an atom. Suchwaves are called non-ionizing radiation.


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The electromagnetic waves, on the other hand, such as x-rays,

gamma rays and cosmic rays are known as ionizing radiation.

These are the rays that carry amounts of energy large enough toremove electrons from the atom, thus making the atom a charged

or an ionized particle.


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What is radioactivity?

some atoms that are unstable and are called

radioactive. These atoms eventually disintegrateinto a totally new atom.

This process of spontaneous transformation of anunstable atom which results in the emission of

radiation is called radioactivity.

Radioactive atoms decay and emit three distincttypes of rays. These are the

alpha particle () for an alpha decay, a beta particle () for a beta decay, and

gamma ray () for a gamma decay.


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Alpha particles consist of two protons and two neutrons in theform of atomic nuclei. They carry a positive electrical charge and

are emitted from naturally occurring heavy elements such as

uranium.Since alpha particles are relatively large they collide readily

with matter and quickly loses this energy, thus they have little

penetrating power. Sheets of paper and skin can easily block

or stop alpha particles.


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X-rays and gamma rays are transmitted through waves.

X-rays are generally artificially produced while gamma rays are

generally emitted from the atomic nucleus. Both have high

penetrating power and can easily pass through the human

body. Only thick barriers of concrete, lead or water can be used

to stop them.


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Isotopes vs Radioisotopes

Isotopes are atoms of the same elements that

have the same atomic number but different

atomic mass.

Radioisotopesare unstable or radioactive

versions of atoms of elements that undergo

decay to become stable and they emit nuclear

radiations during decay


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Types of Decay

Alpha Decayin this type of decay, the atomic number

of the Parent Nucleus decreases by 2, while the

atomic mass number decreases by 4. The resulting

nucleus after the decay is called Daughter nucleus.


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Types of Decay

Beta Decay

Betaminusin this type of decay, the atomic number ofthe Parent Nucleus increases by 1 , while the atomicmass number remains constant.

Beta plusin this type of decay, the atomic number

of the Parent Nucleus decreases by 1 , while the

atomic mass number remains constant.


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Types of Decay

Gamma Decayin this type of decay, the atomic

number and atomic mass of the Parent Nucleus

remains constant.


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ISOTOPES BENEFICIAL USES

CARBON-14 DETERMINING THE AGE OF FOSSILS

COBALT-60 PRESERVE FOOD BY KILLING THE VIRUSES

OR BACTERIA.

USED TO BREED NEW VARIETY OF CROPS.IN AGRICULTURAL PEST, IT IS USED TO

STERILIZE MALE INSECTS MAKING THEM

INCAPABLE OF PRODUCING OFFSPRING.

THORIUM-229 PROLONGS THE LIFE OF FLUORESCENTLIGHTS. TO ENSURE THAT THE COATING

STICKS TO THE PAN. USED TO COLD-

STERILIZE PLASTICS & HEAT SENSITIVE

MATERIALS.


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ISOTOPES BENEFICIAL USES

SODIUM-24 LOCATING LEAKS IN PIPE LINE

AMERICIUM-241 SMOKE DETECTOR.

USED TO ENSURE UNIFORM

THICKNESS IN METAL SHEETSAND PAPER.

NICKEL-63 DETECTING EXPLOSIVES

THALLIUM-204 MEASURING DUSTS AND

POLLUTANT LEVELS


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A patient suffering from thyroid disorder is given an

initial shot of 1.5 grams Iodine-131 whose half life is 8

days. How much of it remains after 40 days?


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initial shot of 1.5 grams Iodine-131 whose half life is 8

days. How much of it remains after 40 days?Time (t)

(days)

Amount (N)

(g)

0 1.5

8 0.75

16 0.375

24 0.1875

32 0.09375

40 0.046875

Given: NO= 1.5 grams

T1/2= 8 days t = 40 days

Solution: Find: N= 0.693/T1/2

N = Noe - t

N = (1.5 g) e (0.693/8) 40

N = 0.0469 grams


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How long will it take for Iodine-131 to be 0.00000001 g

if a patient suffering from thyroid disorder is given an

initial shot of 1.5 grams with a half life of 8 days?Time (t)

(days)

Amount (N)

(g)

0 1.5

8 0.75

? 0.00000001

Given: T1/2= 8 days

NO= 1.5 grams

N = 0.00000001 gSolution: Find: t

t =


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(days)

Amount (N)

(g)

0 1.5

8 0.75

? 0.00000001

Given: T1/2= 8 days

NO= 1.5 grams


t = ln (N/NO)


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(days)

Amount (N)

(g)

0 1.5

8 0.75

? 0.00000001

Given: T1/2= 8 days

NO= 1.5 grams


t = ln (N/NO)

t = ln (1.5 g/ 0.00000001 g)

(0.693/8 days)

t = 217 days


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If we let NO be the original number of nuclei at t=0 and


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If we let NObe the original number of nuclei at t=0 andN be the number of nuclei that have not decayed or

disintegrated after some time t, then the number of

disintegrations is the difference between NOand N.

Thus, the activity represented by A is given by

A = - N /t

The negative sign means that the number of

radioactive nuclei decreases. Furthermore, activity isproportional to the number of radioactive nuclei that

have not disintegrated. A = N where is the decay

constant. Since activity is proportional to the number

of radioactive nuclei present, the activity at any time tis given by A = Aoe

- t

A i ff i f h id di d i i


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initial shot of Iodine-131. The activity of Iodine at the

time it was administered to the patient was 5 .0 Ci.

(a) Find its decay constant and (b) its activity after 21days.


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radiation powerpoint (pysics 10) dog a s fgdgdfffffffffg

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