SPSC LECTURER PHYSICS PAST PAPER 20-01-2025
Lecturer Physics 5 years Past Papers Click Here
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چار آپشن میں سے کسی ایک پر کلک کرنے سے جواب سرخ ہو جائے گا۔
روشنی کی ٹرانسورس فطرت کی تصدیق ______ کے رجحان سے ہوئی؟
Polarization of light
Diffraction of light
Dispersion of light
None of these
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Explanation
Polarization confirms light is a transverse wave because it involves restricting oscillations to a specific plane . For polarization, light must have oscillating components in different planes. Transverse waves have oscillations perpendicular to the direction of wave propagation, allowing polarization.
پی این ڈایڈڈ میں ممکنہ رکاوٹ کی وجہ ______ ہے؟
Depletion of positive charges near the junction
Concentration of positive and negative charges near the junction
Depletion of positive and negative charges near the junction
None of these
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Explanation
The potential barrier in a PN diode is caused by the depletion region, where mobile positive and negative charges near the junction diffuse and leave behind immobile ions. This depletion creates an electric field that opposes further charge movement, forming the potential barrier.
Yielding
Rigid
Movable
Supply
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Explanation
Elastic means لچکدار
Rigid means غیر لچکدار
آپٹیکل فائبر ______ کے اصول پر کام کرتا ہے؟
Laser technology
Photo-electric
Total internal reflectance
None of these
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Explanation
Optical fibers transmit data as light signals.
The signal is confined within the fiber due to the phenomenon where light hits a medium boundary.
It is completely reflected back.
مندرجہ ذیل میں سے کون سا مستقل تابکاری سے متعلق نہیں ہے؟
Boltzmann’s constant
Solar constant
Stefan’s constant
None of these
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Explanation
Boltzmann's constant is primarily related to thermodynamics and kinetic theory, not directly to radiation. Solar, Stefan’s, and Wien’s are directly associated with radiation laws and phenomena.
چاند پر خلاباز کی ریڈیو ٹرانسمیشن زمین پر کتنی دیر بعد موصول ہوگی؟ (زمین سے ملین میٹر)۔
1.27s
0.38s
0.25s
None of these
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Explanation
The distance between the Earth and the Moon is approximately 384,000 kilometers (384 million meters). Using the speed of light (c = 3 × 10⁸ m/s), time = distance/speed = 384 × 10⁶ / 3 × 10⁸ = 1.27 seconds.
ایک مساوی پرزم اور ہوا کا 45 ڈگری کا نازک زاویہ ہوتا ہے۔ اگر آنے والی شعاع ریفریکٹنگ سطح پر کھڑی ہے تو یہ _____؟
It keeps reflecting from all the three sides of the prism and never emerges out
It gets reflected from second and third surfaces and emerges from the first surface
It is reflected from the second surface and emerges perpendicular from the third surface
None of these
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Explanation
Total Internal Reflection (TIR) : Since the critical angle is 45° , and the incident ray is perpendicular to the first surface , it enters without deviation and strikes the second surface at 60° (greater than 45°), causing TIR . Emergence : After reflecting from the second surface, the ray reaches the third surface at 30° , which is less than the critical angle , so it emerges perpendicularly from the third surface .
ذریعہ یا مبصر کی حرکت کی وجہ سے آواز کی مشاہدہ شدہ فریکوئنسی میں کون سا ردوبدل ہے؟
Doppler effect
Thermal effect
Diffraction effect
None of these
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Explanation
The Doppler effect refers to the change in observed frequency of a sound when the source or observer is in motion. It causes the frequency to increase as they move closer and decrease as they move apart.
حرکت پذیر جسم سے وابستہ ڈی بروگلی لہر گروپ _____ رفتار کے ساتھ سفر کرتا ہے؟
Half of the De Broglie wave groups velocity
With which body is moving
One fourth of the velocity with which the body is moving
None of these
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Explanation
The velocity of the De Broglie wave group (group velocity) is equal to the velocity of the particle or body in motion . This is because the De Broglie wave group represents the particle's motion.
جب جسم پر لگائے جانے والے تناؤ کو زیادہ سے زیادہ قیمت سے زیادہ بڑھایا جاتا ہے اور کچھ وقت کے بعد اسے ہٹا دیا جاتا ہے تو کیا ہوتا ہے؟ ینگ کے ماڈیولس کی تعریف ______ کے طور پر کی گئی ہے؟
Tensile stress/tensile strain
Tensile strain/tensile stress
Tensile strain × tensile stress
None of these
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Explanation
Young's modulus is a measure of the stiffness of a material, defined as the ratio of tensile stress to tensile strain within the elastic limit. It quantifies how much a material will stretch or compress under a given force.
