SPSC Physics 25 years Past Papers

Q31: Relativistic Mechanics produces results different from classical mechanics for bodily?

متعلقہ میکانکس جسمانی طور پر کلاسیکی میکانکس سے مختلف نتائج پیدا کرتا ہے؟

Zero velocity

Low velocities

Very high velocities

None of these

Explanation

Relativistic mechanics differs from classical mechanics when objects move at speeds close to the speed of light ( $v approx c$ ).

At low velocities, classical mechanics gives accurate results, but at very high velocities, effects like time dilation and mass increase become significant.

Q32: During one oscillation, phase of oscillation changes by _____?

ایک دوہری کے دوران ، _____ کے ذریعہ دوئم کے مرحلے میں تبدیلی آتی ہے؟

π⁄2 rad

π rad

2π rad

None of these

Explanation

In one complete oscillation (one full cycle), the phase of an oscillating system changes by $2pi$ radians.

This corresponds to the system returning to its starting position in a periodic motion, such as simple harmonic motion.

Q33: Canonical transformations can often be conveniently found or verified by using a ______?

کا استعمال کرکے کیننیکل تبدیلیاں اکثر آسانی سے پائی جاسکتی ہیں یا اس کی تصدیق کی جاسکتی ہیں؟ _____

Separation tensor

Degenerating function

Generating function

None of these

Q34: Divergence of a vector at a point in a vector field is _____ quantity.

ویکٹر فیلڈ میں ایک نقطہ پر ویکٹر کا انحراف _____ مقدار ہے۔

A scalar

A vector

Both A and B

None of these

Q35: Which of the following is the correct relation between current density and magnetization?

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

Explanation

The correct relation between current density ( $mathbf{J}$ ) and magnetization ( $mathbf{M}$ ) is: $J = \nabla \times M$

This equation describes how the curl of magnetization produces bound current density in magnetized materials.

Q36: A student added three figures 72.1, 3.32 and 0.003. The correct answer regrading the rules of the addition of the significant figures will be ______?

75.4

75

75.42

None of these

Q37: The full form of STM is _____?

ایس ٹی ایم کی مکمل شکل _____ ہے؟

Scanning Tunneling Microscope

Scientific Technical Microscope

Systemic Technical Microscope

None of these

Q38: The material which is slightly attracted to a magnetic field is _____?

وہ مواد جو مقناطیسی میدان کی طرف تھوڑا سا راغب ہوتا ہے وہ ______ ہے؟

Paramagnetic

Diamagnetic

Ferromagnetic

None of these

Q39: The range of the coulomb's force is _____?

کولمب کی طاقت کی حد _____ ہے؟

Infinite

r^2

zero

None of these

Q40: Which one of the following is more coherent?

مندرجہ ذیل میں سے کون سا زیادہ مربوط ہے؟

X-rays

Laser

Normal light

None of these