Physics Lecturer Past Paper 20-01-2025

Q41: A beta particle in a single encounter _____?

ایک ہی تصادم میں بیٹا ذرہ _____؟

Loses no energy at all

Loses most of its energy

Loses a small fraction of its energy

None of these

Q42: The hydrogen-like atom has one electron revolving around a stationary nucleus. The energy required to execute electron from the second orbit to the third orbit is 42.7eV. The atomic number of the atom is _______?

3

4

6

None of these

Q43: A closed organ pipe is excited to produce the third overtone of the air column. Then it will have ______?

ایک بند آرگن پائپ ایئر کالم کا تیسرا اوور ٹون پیدا کرنے کے لیے پرجوش ہے۔ معلوم ہوا کہ پائپ میں ہوا ______ ہے؟

Four needs and three antinodes

Three nodes and three antinodes

Three nodes and four antinodes

None of these

Q44: Wien's displacement law is ______?

وین کی نقل مکانی کا قانون ______ ہے؟

𝜆𝑚𝑇= constant

𝜈𝑚𝑇= constant

ν𝜆𝑚 = constant

None of these

Explanation

Wien's Displacement Law states that the product of the wavelength at which a blackbody emits maximum intensity ( $lambda_m$ ) and its absolute temperature ( $T$ ) is constant:
$lambda_m T = text{constant}$ .

It explains the inverse relationship between temperature and peak wavelength.

It meaning hotter objects emit radiation at shorter wavelengths.

Q45: Which of the following is not used as a nuclear fuel cladding material?

مندرجہ ذیل میں سے کون سا جوہری ایندھن کی کلڈنگ مواد کے طور پر استعمال نہیں ہوتا ہے؟

Iron

Cadmium

Ceramics

None of these

Q46: What happens when the stress applied to the body is increased beyond the maximum value and is removed after some time? Young's modulus is defined as ______?

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

Q47: A point charge of 10 X 10^-6 C is at the centre of a cubical Gaussian surface of sides 0.5 m. What is the flux for the surface?

2.45 X 10^5 Nm^2/C

1.12 X 10^5 Nm^2/C

3.12 X 10^5 Nm^2/C

None of these

Q48: The De Broglie wave group associated with a body in motion travels with the velocity _____?

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

Q49: The current through an inductance follows ______?

انڈکٹنس کے ذریعے کرنٹ ______ کی پیروی کرتا ہے؟

An exponential growth

A linear growth

A linear decay

None of these