SPSC 25 YEARS PAST PAPERS 2001 TO 2026
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چار آپشن میں سے کسی ایک پر کلک کرنے سے جواب سرخ ہو جائے گا۔
- Fusion
- Alpha radiation
- Fission
- Beta radiation
- None of these
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Explanation
Uranium-238 () undergoes alpha decay, emitting an alpha particle (), reducing its atomic number by 2 and mass number by 4.This transforms it into Thorium-234 ().
جب ایک نیوکلئس بیٹا ذرات کا اخراج کرتا ہے تو ، والدین اور بیٹی نیوکللی ______ ہوتے ہیں؟
- Isotones
- Nuclear isomers
- Isobars
- None of these
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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.
- Dipole moment
- Fewer electrons than O2
- Two covalent bonds
- None of these
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Explanation
Water () has a high dipole moment, leading to strong hydrogen bonding between molecules.This increases its critical temperature compared to , which has weak intermolecular forces.
- sp^3 d
- sp^3
- sp^2
- None of these
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Explanation
In BH₃, boron forms three sigma bonds with hydrogen and has no lone pairs, leading to sp² hybridization.The molecular geometry is trigonal planar, with 120° bond angles.
تیزابیت کے بعد جو ڈھانچہ باقی رہتا ہے وہ پروٹون کو ____ کہتے ہیں؟
- Conjugate salt
- Conjugate base
- Conjugate acid
- None of these
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Explanation
When an acid donates a proton (), the remaining species is called its conjugate base.For example, HCl (acid) gives up to form Cl⁻ (conjugate base).
- It is chemical reactive
- Its Z is odd
- It is odd-odd nucleus
- None of these
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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.
- Trigonal planner, sp^2
- Tetrahedral, sp^3
- Linear, sp
- None of these
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Explanation
In BF₃, boron forms three sigma bonds with fluorine, adopting sp² hybridization.The molecular geometry is trigonal planar with a 120° bond angle.
اگر کوآرڈینیشن نمبر 6 ہے تو ، رداس _______ ہے؟
- 0.225
- 0.414
- 0.155
- None of these
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Explanation
For a coordination number of 6, the radius ratio () is 0.414 based on ionic packing.This ratio helps determine the stability and geometry of ionic structures.
مندرجہ ذیل میں سے کون سا سپیکٹروسکوپی 7 ای وی کے توانائی کے ذریعہ استعمال کرتا ہے؟
- UV (Ultraviolet) spectroscopy
- Infrared
- Emission spectroscopy
- None of these
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Explanation
UV spectroscopy typically uses energy in the range of 3–7 eV.This making it suitable for electronic transitions.It is widely used to analyze molecular structures and detect conjugated systems.
جوہری فیوژن ، جیسے جوہری فشن ______؟
- Is exoergic
- Involves isotopes of heavy nuclei
- Is a chain process
- None of these
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Explanation
Nuclear fusion releases a huge amount of energy, making it an exoergic process.It powers stars like the Sun by fusing light nuclei (e.g., hydrogen isotopes).
