ریڈیو ایکٹیویٹی کی اکائی ہے۔
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A. Electron ampere
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B. Curie
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C. D. MV
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D. Electron volt
Explanation
1 curie = 3.7x10^10 radioactive decays per second [exactly].
1 becquerel = 1 radioactive decay per second = 2.703x10^-11 Ci.
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A. Boron-14
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B. Nitrogen-14
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C. Oxygen-14
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D. None of these
Explanation
- Beta decay of carbon-14 involves the conversion of a neutron into a proton, emitting an electron (beta particle).
- This changes the atomic number from 6 (carbon) to 7 (nitrogen), forming nitrogen-14.
ایک تابکار ایٹم ایکس ایک بیٹا پارٹیکل خارج کرتا ہے۔ نتیجے میں ایٹم _____؟
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A. None of these
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B. Has an atomic number that is one more than that of X
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C. Must be radioactive
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D. Has a mass number that is one less than that of X
Explanation
- Beta decay occurs when a neutron converts into a proton, emitting a beta particle (electron) and an antineutrino.
- The atomic number increases by 1, but the mass number remains the same.
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A. Proton is changed into neutron
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B. Positron is changed into electrons
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C. None of these
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D. Neutron is changed into proton
Explanation
- In β⁻ decay, a neutron inside the nucleus converts into a proton, emitting a beta particle (electron) and an antineutrino.
- This process increases the atomic number by +1 while keeping the mass number unchanged.
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A. None of these
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B. 12000 years
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C. 9000 years
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D. 6000 years
Explanation
If the radioactivity is half of that in fresh wood, the time elapsed is equal to one half-life of C-14, which is 6000 years.
Therefore, the tomb is approximately 6000 years old.
جب ایک نیوکلئس بیٹا ذرات کا اخراج کرتا ہے تو ، والدین اور بیٹی نیوکللی ______ ہوتے ہیں؟
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A. Isotones
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B. None of these
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C. Isobars
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D. Nuclear isomers
Explanation
- In beta decay (), a neutron converts into a proton, increasing the atomic number by 1 while keeping the mass number the same.
- Parent and daughter nuclei have the same mass number (A) but different atomic numbers (Z), making them isobars.
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A. Its Z is odd
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B. It is odd-odd nucleus
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C. None of these
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D. It is chemical reactive
Explanation
- 50P15 (Phosphorus-50) has both an odd proton number (Z = 15) and an odd neutron number (N = 35), making it unstable.
- Most odd-odd nuclei are unstable due to nuclear pairing effects.
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A. γ-emission
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B. Proton
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C. α-emission
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D. β-emission
Explanation
The radioactive decay equation shows a parent nucleus (91Pa^233) decaying into a daughter nucleus (92U^233) with the emission of a particle.
The parent nucleus has an atomic number of 91 (Protactinium), and the daughter nucleus has an atomic number of 92 (Uranium).
This increase in atomic number indicates that a beta particle (β) has been emitted.
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A. None of these
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B. 30 days
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C. 10 days
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D. 20 days
Explanation
The substance reduces to (1/16) = (1/2)^4 of its original mass.
This means 4 half-lives = 40 days
So, 1 half-life = 40 / 4 = 10 days
کیوری ______ کی اکائی ہے؟
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A. Radioactivity
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B. None of these
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C. Conductivity
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D. Resistivity
Explanation
Curie (Ci) is a unit that measures the rate of radioactive decay.
1 Curie = 3.7 × 10¹⁰ disintegrations per second.
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