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Correct Answer Logic:
Since \(\vec{u}\) is coplanar with \(\vec{a}\) and \(\vec{b}\), we can write \(\vec{u} = x\vec{a} + y\vec{b} = x(2\hat{i}+3\hat{j}-\hat{k}) + y(\hat{j}+\hat{k}) = 2x\hat{i} + (3x+y)\hat{j} + (-x+y)\hat{k}\). Condition \(\vec{u} \perp \vec{a}\): \(\vec{u} \cdot \vec{a} = 2x(2) + (3x+y)(3) + (-x+y)(-1) = 0\), giving \(4x + 9x + 3y + x - y = 0\), so \(14x + 2y = 0\), thus \(y = -7x\). Condition \(\vec{u} \cdot \vec{b} = 24\): \((3x+y)(1) + (-x+y)(1) = 24\), giving \(3x+y-x+y = 24\), so \(2x+2y = 24\), thus \(x+y = 12\). From \(y=-7x\): \(x-7x = 12\), so \(-6x=12\) and \(x=-2\), giving \(y=14\). Thus \(\vec{u} = -4\hat{i} + 8\hat{j} + 16\hat{k}\), and \(|\vec{u}|^2 = 16 + 64 + 256 = 336\).
Uploaded by: Fani Warraich
General Knowledge QUESTION #2593
Question 3162
In the decimal (base-10) number system, how many unique digit symbols are available for use?
  • 8 digits (0 to 7)
  • 9 digits (1 to 9)
  • 10 digits (0 to 9)✔️
  • 16 digits (0 to 9 and A to F)
Correct Answer Logic:
In the decimal system, there are 10 possible numbers you can use ranging from zero to nine (0, 1, 2, 3, 4, 5, 6, 7, 8, 9). This is why it is called 'base-10' — it has a base of ten distinct symbols.
Uploaded by: Fani Warraich
Math Physics Chemistry Biology QUESTION #739
Question 3163
The range of visible wavelength spectrum is:
  • 400-750 nm✔️
  • 100-400 nm
  • 400-1000 nm
  • 300-600 nm
Correct Answer Logic:
The visible light spectrum ranges from approximately 400 nm (violet) to 750 nm (red).
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Urdu QUESTION #5249
Question 3164
'اس آباد خرابے میں' کس کی خود نوشت ہے؟
  • کلیم عاجز
  • اختر الایمان
  • عبدالمجید سالک✔️
  • اظہر وقار اظیم
Correct Answer Logic:
اس آباد خرابے میں عبدالمجید سالک کی خود نوشت سوانح عمری ہے۔
Uploaded by: Fani Warraich
Paper-I (Anatomy/Physiology and Biochemistry/Microbiology) QUESTION #3211
Question 3165
'Negative Feedback' mechanism is used by the body to:
  • Increase a stimulus continuously
  • Oppose a change and restore balance✔️
  • Store fat
  • Produce sound
Correct Answer Logic:
Most hormones are regulated by negative feedback to maintain homeostasis.
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Boilers Mechanical Engineering QUESTION #2444
Question 3166
The transmissibility (TR) in vibration isolation represents:
  • Output force at support divided by static force
  • The ratio of force transmitted to the foundation to the applied excitation force: \(TR = \sqrt{\frac{1+(2\zeta r)^2}{(1-r^2)^2+(2\zeta r)^2}}\) where \(r=p/\omega_n\)✔️
  • The ratio of damped to undamped amplitude
  • The ratio of kinetic to potential energy
Correct Answer Logic:
Transmissibility: \(TR=F_{transmitted}/F_0=\sqrt{\frac{1+(2\zeta r)^2}{(1-r^2)^2+(2\zeta r)^2}}\). For effective isolation, TR < 1 requires \(r > \sqrt{2}\).
Uploaded by: Fani Warraich
Geography QUESTION #6345
Question 3167
The concept of 'time-space convergence' in economic geography refers to:
  • Increasing speed reducing effective distance between places✔️
  • Synchronization of time zones for global business
  • Historical convergence of development levels
  • Urban areas expanding into rural zones
Correct Answer Logic:
Time-space convergence describes how transport/communication improvements reduce travel time between places, making them functionally closer despite unchanged physical distance. A trip taking weeks in the 1800s now takes hours, facilitating globalization.
Uploaded by: Fani Warraich
Correct Answer Logic:
From \(\vec{a} \times \vec{c} + \vec{b} = \vec{0}\), we get \(\vec{a} \times \vec{c} = -\vec{b}\). Taking dot product with \(\vec{a}\): \(\vec{a} \cdot (\vec{a} \times \vec{c}) = -\vec{a} \cdot \vec{b}\). Since \(\vec{a} \cdot (\vec{a} \times \vec{c}) = 0\), we have \(\vec{a} \cdot \vec{b} = 0\), which checks: \((1)(-1)+(-1)(1)+(0)(1) = 0\). Nope: \(\vec{a} = \hat{i}-\hat{j}\) (only 2D) and \(\vec{b} = \hat{i}+\hat{j}+\hat{k}\), so \(\vec{a} \cdot \vec{b} = 1-1 = 0\). Good. Taking magnitude: \(|\vec{a} \times \vec{c}| = |\vec{b}| = \sqrt{3}\). Also \(|\vec{a} \times \vec{c}|^2 = |\vec{a}|^2|\vec{c}|^2 - (\vec{a} \cdot \vec{c})^2\), so \(3 = 2|\vec{c}|^2 - 16\), giving \(|\vec{c}|^2 = \frac{19}{2}\).
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Boilers Mechanical Engineering QUESTION #3981
Question 3169
The 'Economizer' in a boiler system is used to heat:
  • The fuel before combustion
  • Feed water using flue gases✔️
  • The steam to make it superheated
  • The air entering the furnace
Correct Answer Logic:
Economizers improve efficiency by recovering waste heat from exhaust gases to pre-heat feed water.
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Correct Answer Logic:
A major scientific discovery is best described as a 'breakthrough.'
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Pharmacology and Toxicology QUESTION #3853
Question 3171
Through which mechanism does allopurinol lower serum uric acid levels?
  • To increase renal excretion of uric acid
  • To inhibit formation of uric acid✔️
  • To inhibit absorption of dietary purines
  • To inhibit prostaglandin synthesis
Correct Answer Logic:
Allopurinol inhibits xanthine oxidase, thereby reducing the enzymatic conversion of hypoxanthine and xanthine to uric acid.
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Ability / HR / Governance / Special Education QUESTION #1903
Question 3172
Under Rule 3(d) retention in service of a government servant engaged in subversive activities must be what for action to be taken?
  • Contrary to departmental policy
  • Prejudicial to national security✔️
  • Against the wishes of the Prime Minister
  • Contrary to NAB guidelines
Correct Answer Logic:
Rule 3(d) specifically requires that the government servant's retention in service must be prejudicial to national security as the additional condition for action on grounds of subversive activities or disclosure of official secrets.
Uploaded by: Fani Warraich
Math Physics Chemistry Biology QUESTION #4199
Question 3173
Which of the following best describes the relationship between endoplasmic reticulum (ER) and Golgi apparatus?
  • Both ER and Golgi apparatus are completely separate organelles with no interaction
  • ER is precursor organelle to Golgi apparatus because material is transported from ER to Golgi✔️
  • Golgi apparatus is precursor organelle to ER because material is transported from Golgi to ER
  • ER and Golgi apparatus have similar roles
Correct Answer Logic:
ER synthesizes proteins/lipids that are transported to Golgi apparatus for processing and packaging.
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Correct Answer Logic:
Section 48A(2) states: 'the Revising Authority shall issue a notice to him to appear before it within fifteen days and require him to sign a declaration... regarding his belief about the absolute and unqualified finality of the Prophethood of Muhammad (peace be upon him).'
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Correct Answer Logic:
? = (R??R?)/(R??T) = 100/(100?100) = 0.01 K??, but answer key shows D
Uploaded by: Fani Warraich
Correct Answer Logic:
$\frac{\partial Q}{\partial x} = 2x^3y$, $\frac{\partial P}{\partial y} = 2xy^3$. So $\iint_R (2x^3y - 2xy^3) dA = \int_0^3\int_0^2 (2x^3y - 2xy^3) dy dx = 18$.
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Paper-II (Pharmacognosy and Pharmaceutics-I) QUESTION #2976
Question 3177
The 'Ebers Papyrus' is an ancient document related to the pharmacy of which civilization?
  • Greek
  • Roman
  • Egyptian✔️
  • Chinese
Correct Answer Logic:
The Ebers Papyrus (1550 BC) is one of the most important pharmaceutical records of Ancient Egypt.
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General Knowledge QUESTION #8828
Question 3178
The constellation 'Southern Cross' (Crux) consists of how many main stars?
  • Seven Stars
  • Four Stars✔️
  • Five Stars
  • None of these
Correct Answer Logic:
The Southern Cross has four main stars.
Uploaded by: Fani Warraich
Correct Answer Logic:
'In addition' signals that incorporating African music is a second example of how Coleridge-Taylor emphasized his mixed-race ancestry.
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Physics QUESTION #7321
Question 3180

The velocity of a particle is given by $v = At + Bt^2$, where $A$ and $B$ are constants. The distance travelled between $t = 1\text{ s}$ and $t = 2\text{ s}$ is:

  • $\dfrac{3}{2}A + 4B$
  • $3A + 7B$
  • $\dfrac{3}{2}A + \dfrac{7}{3}B$✔️
  • $\dfrac{A}{2} + \dfrac{B}{3}$
Correct Answer Logic:

$x = \displaystyle\int_1^2 v\,dt = \int_1^2 (At + Bt^2)\,dt = \left[\dfrac{At^2}{2} + \dfrac{Bt^3}{3}\right]_1^2$

$= \left(\dfrac{4A}{2} + \dfrac{8B}{3}\right) - \left(\dfrac{A}{2} + \dfrac{B}{3}\right) = \mathbf{\dfrac{3A}{2} + \dfrac{7B}{3}}$

Uploaded by: Fani Warraich