1. Radioactivity is the process by which certain unstable atomic nuclei spontaneously decay and emit radiation. This involves the emission of particles or electromagnetic waves during nuclear transformations. 2. There are three main types of radiation emitted in radioactivity - alpha, beta and gamma rays. Alpha particles have low penetration power whereas gamma rays have the highest penetration power. 3. Radioactive decay can be used in various applications like cancer treatment, food preservation and dating very old objects. Precise control and knowledge of radioactive decay allows for safe use of radioactivity in nuclear technology and medicine.

1. Created by Debiprasad Dey

4. cigvYyi †K‡›`ª †h ¶z`Zg As‡k
cigvYyi mg¯— ab¥vÍK Avavb I fi †K›`ªxf‚Z _v‡K †mB
AskwU†K wbDwK¬qvm ev †K›`ªK ev †Kw›`ªb e‡j |

5. Av‡cw¶K
AvKvi
bvg fi (kg) Zwo`vavb (c)
wbDUªb 1.67x10-27 +1.602x10-19
†cÖvUb 1.67x10-27 0
B‡jKUªb 9.11x10-31 -1.602x10-19

6. B‡jKUªb†fvë t-GKwU B‡jKUªb 1 v wefe
cÖ‡f‡`i ga¨ w`‡q hvIqvi mgq Zvi MwZkw³ †h cwigvY
e…w× ev nªvm cvq Zv‡K 1 eV ejv nq |
1eV = GKwU B‡jKUª‡bi Zwor Avavb x 1 V
= 1.6 x 10-19C x 1 V
= 1.6 x 10-19 J [since C x V=J]
= 1.6 x 10-19 x 10-7 erg
= 1.6 x 10-12 erg

7. wbDwK¬q ej t- †h e‡ji cÖfv‡e
GKB Zwo`vavb hy³ †cÖvUb I
wbDUªb Kbv¸wj wbDwK¬qv‡mi g‡a¨
GKm‡½ _vK‡Z cv†i Zv‡K wbDwK¬q
ej e‡j |
Zwor weKl©b e‡ji
cÖfv‡e wbDwK¬qvmwU
†f‡½ †h‡Z PvB| wKš‘
kw³kvjx wbDwK¬q ej
†cÖvUb¸wj†K GKm‡½
_vK‡Z mvnvh¨ K‡i |

8. [RADIOACTIVITY]
D”P cvigvbweK µgvOK hy³ KZK¸wj fvix †gŠ‡ji
cigvYyi wbDwK¬qvm, †h †Kv†bv Ae¯’vq wb‡R †_‡KB
¯^Ztù‚Z©fv‡e Aweivg MwZ‡Z wefvwRZ n‡q bZzb †gŠ‡ji
wbDwK¬qv‡m cwiYZ nq Ges †mB m‡½ GK we‡kl ai‡bi
A`„k¨ iwk¥ wewKib K‡i | hv AÜKv‡i †dv‡UvMÖvwdK
†c­Z‡K Avµvš— K‡i , cvZjv avZe cvZ †f` K‡i Ges
M¨v‡mi ga¨ w`‡q hvevi mgq Zv‡K AvqwbZ K‡i | GB
wewKwiZ iwk¥¸wj Av†jvK , Pvc, DòZv,ivmvqwbK
wewµqv cÖf…wZ †KvbI Kvib ØvivB cÖfvweZ nq bv | fvix
†gŠ‡ji cigvYyi Giƒc iwk¥ wewKib ag©‡K †ZRw¯ŒqZv
e‡j |

10. α
Avjdv iwk¥
β
weUv iwk¥
y
Mvgv iwk¥
cÖK…wZ
Avjdv iwk¥ aœb¥vÍK (+)
Avavb hy³ ¶z`ª ¶z`ª c`v_©
Kbvi mgwó | Zxeª †e‡M
wbM©Z nq e‡j iwk¥ e‡j
g‡b nq| GwU GKwU
wnwjqvg 2He4 wbDwK¬qv‡mi
g‡Zv |
weUv iwk¥ FbvÍK (-)
Avavb hy³ ¶z`ª ¶z`ª
c`v_© Kbvi mgwó | Zxeª
†e‡M wbM©Z nq e‡j
iwk¥ e‡j g‡b nq| GwU
GKwU B‡jKUª‡bi -1 e0
g‡Zv |
GwU AwZ ¶z`ª
Zi½•`N¨© wewkó
ZworPz¤^Kxq Zi½ |
Avavb +2 GKK ev 9.6x10-10 esu -1 GKK ev 4.8x10-10 esu 0 ev wbt¯—woZ
fi 6.642 x 10-24 g
9.108 x 10-28 g. fi cÖvq
†bB ej‡jB P‡j |
fi †bB |
†f`b ¶gZv
fi †ewk I †eM Kg
nIqvB Avjdv Kbvi †f`b
¶gZv me‡P‡q Kg |
Avjdv iwk¥ 0.1 mm cyi“
A¨vjywgwbqvg cvZ Øviv
†kvwlZ nq |
fi bMY¨ I †eM D”PZi
nIqvB weUv Kbvi †f`b
¶gZv Lye †ewk| weUv
iwk¥ 5 mm cyi“
A¨vjywgwbqvg cvZ †f`
K‡i †h‡Z cv‡i |
Mvgv iwk¥i †f`b
¶gZv me‡P‡q †ewk |
GwU 8 cm cyi“
A¨vjywgwbqvg cvZ
†f` K‡i †h‡Z cv‡i |
M¨vm‡K AvqwbZ
Kivi ¶gZv
me‡P‡q †ekx|
Kg | Avjdv Kbvi
100 fv‡Mi 1 fvM|
LyeB Kg|

12. K‡qKwU cwiwPZ †ZRw¯Œq †gŠj

13. nvU© -Gi
wPwKrmv
K¨vÝv‡ii
wPwKrmv
cvigvbw
eK we`¨yr
Drcv`b
†K‡›`ª
wKQz e¨envi‡hvM¨ †ZRw¯Œq †gŠj

17. hviv GKUz †ewk
Rvb‡Z PvI ev Rvbv‡Z
PvI Zv‡`I Rb¨ |
bv n‡j w¯‹c Ki‡Z
cv‡iv |

19. †ZRw¯ŒqZvi GKK mg~n

20. wbDwK¬qvm wbDwK¬qb ( †cÖvUb I wbDUªb) wb‡q MwVZ| A_¨©vr wbDwK¬qv‡mi fi †cÖvUb I wbDUª†bi †gvU
f‡ii m‡½ mgvb n‡e| wKš‘ †`Lv †M‡Q wbDwK¬qv‡mi w¯’ifi I wbDwK¬qb ¸wji †gvU f‡ii g‡a¨ wKQz
cv_©K¨ _‡K | GB cv_©K¨ m~PK fi‡K fi weP¨ywZ ev fi ΂wU e‡j |
A_¨©vr hw` †Kvb †gŠ‡ji cvigvweK msL¨v ZGes fimsL¨v A nq,
Zvn‡j cigvYyi wbDwK¬qv‡m †cÖvUb msL¨v = Z
wbDUªb msL¨v = A-Z
GLb hw` GKwU †cÖvU‡bi fi mp nq Ges GKwU wbDUª‡bi fi mn nq
Zvn‡j wbDwK¬qvmwUi fi = Zmp + (A-Z)mn
hw` wbDwK¬qv‡mi w¯’i fi M nq
Zvn‡j fi ΂wU Zmp + (A-Z)mn
a¨vZ
†ZwiwK ...?

21. wbDwK¬qv‡mi †cÖvUb I wbDUªb ¸wji fi nªv‡mi d‡j m~Î n‡Z cÖvß †h we‡kl kw³i
Øviv wbDwK¬qb¸wj †RvUe× Ae¯’vq _vK‡Z cv‡i Zv‡K eÜb kw³ e‡j |
A_¨©vr †h cwigvY f‡ii ΂wU N‡U †mB cwigvY f‡ii Zzj¨ kw³B nj eÜb kw³i
cwigvY |
AZGe eÜb kw³ = c2
Zmp + (A-Z)mn c2

22. †h wbDK¬xq wewµqvq A‡c¶vK…Z fvix †gŠ‡ji wbDwK¬qvm cÖvq mgvb f‡ii `ywU
wbDwK¬qv‡m wefvwRZ nq I cÖPÊ kw³i gyw³ NUvq Zv‡K wbDK¬xq wefvRb
e‡j |
Uv†M©U

23. wbDwK¬q wefvRb
axi MwZ m¤cbœ wbDUªb
Uv†M©U
k„•Lj
wewµqv

24. wbDK¬xq wefvRb wewµqvi AvÜKvi w`KwU nj cigvYy †evgv | wbDK¬xq wefvR†bi k„•Lj wewµqv‡K Kv‡R jvwM‡q
cigvYy †evgv •Zix Kiv nq | hvi ¶wZKi cÖfve bvMvmvwK I wn‡ivwkgv eû cÖRb¥ a‡i †fvM K‡i P‡j‡Q | wn‡ivwkgvq
BD‡iwbqvg †evgv Ges bvMvmvwK‡Z c­‚‡Uvwbqvg †evgv †djv n‡qwQj | †evgvi ¶gZv GZ †ewk wQj †h †evgv †djvi m‡½
m‡½ 500 wgUvi †iwWqv‡m 90% gvbyl gviv wM‡qwQj | hviv †eu‡P wQj wZb mßv‡ni g‡a¨ Zv‡`I g‡a¨ Pzj IVv ,
A¨vwbwgqv , i³víZv , K¨vbmvi , cÖf…wZ †ivM †`Lv wM‡qwQj |

25. wbDK¬xq wiA¨v±i
wbDK¬xq wiA¨v±i nj †mB e¨e¯’v hvi Øviv wbDK¬xq wefvRb †K gvbe Kj¨v‡Y e¨envi Kiv hvq |
wbDK¬xq wiA¨v±i ev wbDwK¬q Pzwj­†Z wbqwš¿Z wbDwK¬q wefvRb Øviv wefvR‡b Drcbœ kw³‡K
cÖ‡qvRb g‡Zv e¨envi K‡i - 1. we`¨yr kw³ Drcv`b ( 1 †KwR Kqjv cywo‡q hv Zvc cvIqv hvq Zvi †_‡K 30 j¶¸b
†ewk Zvc cvIqv hv‡e 1 †KwR BD‡iwbqvg †_‡K |)
2. †ZRw¯Œq AvB‡mv‡Uvc Drcv`b
3. wbDUª‡bi Zxeª iwk¥ Drcv`b cÖf…wZ KvR Kiv nq |

26. wbDwK¬q `yN©Ubv
wbDwK¬q Pzwj- , wPwKrmv†¶Î , j¨ve‡iUwi†Z e¨eüZ †Z·wµq AvBmZc¸wj †_‡K wbM©Z †ZRw¯Œq Kbv
cwi‡e‡k †h wech©q NUvq Zv‡K wbDwK¬q `yN©Ubv e‡j |
wbDwK¬q `yN©Ubvi `ywU cwiwPZ D`vnªb nj †Pi‡bvwej I dzKzwkgvi cvigvbweK `yN©Ubv |
†ZRw¯Œ q weNU‡bi d‡j gvbe †`‡n `ycÖKvi ¶wZ nq - 1. c¨v†_vjwRK¨vj
2. †R‡bwUK

27. wbDwK¬q ms†hvRb
†h wbDwK¬q wewµqvq K‡qKwU nvév †gŠ‡ji wbDwK¬qvm ci¯ci hy³ n‡q fvix †gŠ‡ji wbDwK¬qvm
•Zix K‡i Zv‡K wbDwK¬q ms†hvRb e‡j |
wbDwK¬q ms†hvRb wewµqvi cÖ‡qvRbxq kZ© ¸wj nj nvjKv wbDwK¬qvm Ges cÖPzi Zvc kw³ |

28. nvBWª‡Rb †evgv nj cvigvbweK †evgv A‡c¶v eû¸b weaŸsmx ¶gZvm¤cbœ GKwU AwZ
kw³kvjx we‡ùviK |GwU wbDwK¬I ms†hvRb wewµqvi bxwZi Dci wfwË K†i cÖ“¯‘z Z Kiv nq |
GB †evgvi †K‡›`ª Wq†Uwiqvg Ges wjw_qvg AvB‡mv‡Uv‡ci wgkªY _v‡K |