SPSC PHYSICS 25 YEARS PAST PAPERS
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چار آپشن میں سے کسی ایک پر کلک کرنے سے جواب سرخ ہو جائے گا۔
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.
کسی شخص پر ماحول کے ذریعہ فورس کا استعمال _____ ہے؟
200000 N
400000 N
500000 N
None of these
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Explanation
The atmospheric pressure at sea level is about 101,325 Pa (N/m²) , and the average surface area of a human body is around 2 m² . The total force exerted is:
F = P × A = 101 , 325 × 2 ≈ 200 , 000 N This force is balanced by the internal pressure of the body , so we don’t feel it.
وہ مواد جو مقناطیسی میدان کی طرف تھوڑا سا راغب ہوتا ہے وہ ______ ہے؟
Paramagnetic
Diamagnetic
Ferromagnetic
None of these
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Explanation
Paramagnetic materials are slightly attracted to a magnetic field due to the presence of unpaired electrons . Unlike ferromagnetic materials , they do not retain magnetization when the external field is removed.
متعلقہ میکانکس جسمانی طور پر کلاسیکی میکانکس سے مختلف نتائج پیدا کرتا ہے؟
Zero velocity
Low velocities
Very high velocities
None of these
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Explanation
Relativistic mechanics differs from classical mechanics when objects move at speeds close to the speed of light (v ≈ c v approx c At low velocities , classical mechanics gives accurate results, but at very high velocities , effects like time dilation and mass increase become significant.
200 mF
500 mF
300 mF
None of these
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Explanation
When capacitors are connected in series, the total capacitance (C_total) is given by:
1/C_total = 1/C1 + 1/C2
Given:
C1 = 300 mF
C2 = 600 mF
1/C_total = 1/300 + 1/600
= (2 + 1) / 600
= 3 / 600
= 1 / 200
C_total = 200 mF
ایک نوڈ اور اینٹینوڈ کے درمیان مرحلے کا فرق _____ ہے؟
280°
90°
45°
None of these
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Explanation
In a standing wave , the phase difference between a node (zero displacement) and an antinode (maximum displacement) is 90° (π/2 radians) .This means that when the antinode reaches maximum displacement, the node remains at rest.
Plate
Cube
Sphere
None of these
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Explanation
The rate of cooling follows Newton’s Law of Cooling , which depends on surface area. The thin circular plate has the largest surface area-to-volume ratio. This allowing it to lose heat faster than the cube or sphere.
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.
a/(4/√3)
a/4/13)
al(4/12)
None of these
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Explanation
In a Body-Centered Cubic (BCC) lattice, the relation between the lattice parameter a and atomic radius r is:
4 r = 3 a Since atomic diameter = 2r , solving gives:
Atomic Diameter = 4 r 2 = a 4 / 3
موجودہ کثافت اور میگنیٹائزیشن کے مابین مندرجہ ذیل میں سے کون سا صحیح تعلق ہے؟
J = Grad(M)
J = Div(M)
J = Curl(M)
None of these
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Explanation
The correct relation between current density (J mathbf{J} M mathbf{M} is:
J = ∇ × M This equation describes how the curl of magnetization produces bound current density in magnetized materials.
