LECTURER PHYSICS PAST PAPER 03-06-2023 BY SPSC
Lecturer Physics 25 years Past Papers Click here
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چار آپشن میں سے کسی ایک پر کلک کرنے سے جواب سرخ ہو جائے گا۔
کولمب کی طاقت کی حد _____ ہے؟
Infinite
r^2
zero
None of these
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Explanation
Coulomb’s force follows the inverse square law , meaning it decreases with distance but never becomes exactly zero . Since there is no definite boundary where the force completely vanishes, its range is considered infinite .
اگر چارجز کے درمیان فاصلہ دوگنا ہوجاتا ہے تو ، چارجز کے درمیان کولمب کی طاقت _____؟
One-fourth
Halves
Distance between the charges
None of these
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Explanation
According to Coulomb’s Law , the electrostatic force F F is inversely proportional to the square of the distance between the charges: F ∝ 1 r 2 F propto frac{1}{r^2} If the distance doubles (r → 2 r r to 2r , the force reduces to one-fourth of its original value: F ′ = F 4 F' = frac{F}{4}
An atom with a specified number of protons and neutrons
The nucleus of the atom
A subatomic particle
None of these
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Explanation
Isotopes are atoms of the same element that have the same number of protons but different numbers of neutrons .This difference in neutrons gives them different atomic masses while retaining the same chemical properties .
مندرجہ ذیل میں سے کون سا زیادہ مربوط ہے؟
X-rays
Laser
Normal light
None of these
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Explanation
Coherence refers to the phase consistency of a wave over time and space. Laser light is highly coherent because it emits waves that are monochromatic , in phase, and travel in the same direction .
75.4
75
75.42
None of these
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Explanation
The rule for addition of significant figures states that the result should have the same number of decimal places as the number with the fewest decimal places. Given numbers : 72.1 (1 decimal place)3.32 (2 decimal places)0.003 (3 decimal places)Sum: 72.1 + 3.32 + 0.003 = 75.423 Rounding to one decimal place (as in 72.1), the final answer is 75.4 .
ایس ٹی ایم کی مکمل شکل _____ ہے؟
Scanning Tunneling Microscope
Scientific Technical Microscope
Systemic Technical Microscope
None of these
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Explanation
Scanning Tunneling Microscope (STM) is a powerful tool used to image surfaces at the atomic level using quantum tunneling . It was invented by Gerd Binnig and Heinrich Rohrer in 1981. It is widely used in nanotechnology .
نینو ٹکنالوجی میں مندرجہ ذیل میں سے کون سا اطلاق نہیں کرتا ہے؟
Newtonian mechanics can describe it
It can be called green technology
It is general-purpose technology
None of these
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Explanation
Nanotechnology deals with materials at the nanoscale (1-100 nm) , where quantum mechanics is required instead of Newtonian mechanics .Newtonian mechanics fails at this scale because quantum effects dominate, influencing electrical, optical, and mechanical properties .
مواد کی ریفریجویٹ انڈیکس تقریبا _____ کے مربع جڑ کے برابر ہے؟
Magnetic permeability
Electrical permittivity
Electrical permittivity × Magnetic permeability
None of these
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Explanation
The refractive index (n) of a material is given by:
n = μ ε n = sqrt{mu varepsilon}
where μ is the magnetic permeability and ε is the electrical permittivity of the material. This relation shows how light propagation depends on both electric and magnetic properties of the medium.
سیمیکمڈکٹر میں چارج کیریئر کی نقل و حرکت کا انحصار _____ کے ذریعہ دیا گیا ہے؟
μ ∝ 1/T
μ ∝ T¹/²
μ ∝ 1/T¹/²
None of these
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Explanation
The mobility (μ) of charge carriers in a semiconductor is inversely proportional to the square root of temperature (T) due to increased lattice scattering at higher temperatures. This relation is expressed as μ ∝ 1/T¹/² , meaning mobility decreases as temperature increases.
فیرومیگنیٹک مواد _____ سے حاصل کیا جاتا ہے؟
Aluminum
Nickel
Copper
None of these
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Explanation
Ferromagnetic materials exhibit strong magnetism due to the alignment of magnetic domains. Nickel (Ni) is a ferromagnetic material, along with iron (Fe) and cobalt (Co) , whereas aluminum and copper are non-magnetic .
