Welcome to Physics Initial Test 8, an advanced online practice module designed specifically for candidates preparing for the initial academic tests of the Pakistan Armed Forces—including Pakistan Air Force (PAF) (GDP, CAE, Aeronautical Engineering, Airmen), Pak Army (Technical Cadet Course – TCC), and Pak Navy (PN Cadet, Operations, Engineering Branches).
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#1. The second law of thermodynamics is concerned with the situation in which
#2. The percentage efficiency of Carnot’s engine
#3. The unit of thermodynamic temperature scale is
#4. Physics is one of the branches of
#5. The average speed of oxygen molecule in the air at S.T.P. is
#6. Which expression represents a NAND operation?
#7. A common point between OR and AND gates is that
#8. The production of electrons in a cathode-ray tube is
#9. A sinusoidal trace is observed on a CRO screen. For this alternating potential was given to
#10. If a charge Q is dispersed over two spheres of radii R and r such that their surface charge densities are equal. What is the ratio of the charges on the spheres?
#11. There are three bulbs of 60W, 100W and 200 W which bulb has thickest filament.
#12. Scalar product of a vector A with itself is
#13. Electrical energy is measured in
#14. Electrical energy is converted to heat at the rate of
#15. Which one of the following bulbs has the least resistance?
#16. Which one of the following is scalar?
#17. Transformer works on
#18. The neutral point in a magnetic field will be a point at which
#19. At Curie temperature the ferromagnetic materials get converted into
#20. A galvanometer gives full scale deflection when the current passing through it is 1mA. Its resistance is 100 Omega. Without connecting additional resistance in series with it, it can be used as a voltmeter of range.
#21. The needle of the dip circle at a place stays at 30°. The dip circle is inclined at an angle of 30° with the magnetic meridian. The true dip at the place is
#22. If in a photoelectric cell, the wavelength of incident light is changed from 4000 A to 3600 A, then the change in stopping potential will be
#23. A stopping potential of 0.82 volt is required to stop the photo electron emitted from a metallic surface by light wavelength 400A. The stopping potential for wavelength 3000A will be
#24. A block of mass m and charge q is place on a smooth horizontal table which terminates in a vertical wall at a distance d from the block. A horizontal electric field E toward right is switched on. Assuming elastic collision, find time period of the resulting oscillatory motion.
#25. The center of gravity of a cylinder is at
#26. When an electron jumps from a higher to a lower orbit, the energy of the photon emitted depends upon
#27. How can we increase the period of oscillation of a mass spring system?
#28. Which one of the following is a vector quantity?
#29. Threshold frequency is the frequency below which
#30. Lenz’s low provides a relation between
#31. Which one of the following properties of waves is not found collectively in both sound waves and radio waves?
#32. For rectifying action we use
#33. Which one of the following is the dimensional formula for angular momentum?
#34. Magnetic flux passing normally through a unit area is called
#35. Photo cell works
#36. A heat engine working in between two isothermals and two adiabatic is called
#37. Resistance of a conductor increases as its
#38. A satellite is orbiting round the earth in a circular orbit. It moves with
#39. In order to observe two successive bright or dark fringes in Michelson’s interferometer, the movable mirror is displaced through a distance of
#40. Which one of the following discarded the idea of either?
#41. A body of mass m is moving in a circle of radius r with a constant speed v. The force on the body is mv^2/r and is directed towards the center. What is the work done by this force in moving the body over half the circumference of the circle?
#42. The unit of torque in SI system is
#43. If a simple pendulum is vibrating then (I) Length of pendulum and time period is directly proportional, (II) Time period of pendulum is independent of the mass of the bob, (III) Time period depends upon the value of the g.
#44. According to Bohr’s theory of hydrogen atom, the angular momentum of electron in allowed orbit is
#45. A lift is failing freely after the breakdown of its suspension. The weight of person inside the lift would become
#46. Clock-wise torque is taken as
#47. The unit of Plank’s constant in C.G.S system of units is
#48. A ball is thrown horizontally from the of 490 m high cliff with a velocity of 10 m/sec. It experiences (I) Horizontal acceleration equal to zero, (II) Vertical acceleration of 9.8 m/sec^2, (III) Angular acceleration of 9.8 rad/sec^2
#49. A source of sound waves towards a stationary observer. The apparent frequency heard by the observer is
#50. Resistivity of a conductor is of the order of
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PHYSICS INITIAL TEST 8
Welcome to Physics Initial Test 8, an advanced online practice module designed specifically for candidates preparing for the initial academic tests of the Pakistan Armed Forces—including Pakistan Air Force (PAF) (GDP, CAE, Aeronautical Engineering, Airmen), Pak Army (Technical Cadet Course – TCC), and Pak Navy (PN Cadet, Operations, Engineering Branches). This practice quiz focuses on electromagnetic wave propagation, semiconductor electronics, operational amplifiers, atomic energy transitions, and high-frequency multiple-choice questions needed to clear your computer-based military entrance exam with distinction.
Key Topics Covered in Physics Initial Test 8
To secure top marks in the Physics academic paper during your Armed Forces selection test, make sure to thoroughly revise these core physical concepts assessed in this module:
- Electromagnetic Waves & Propagation: Speed of electromagnetic radiation, energy density in electric and magnetic fields, Poynting vector, and spectrum classifications.
- Semiconductor Physics & Diodes: Intrinsic and extrinsic semiconductors, doping concentrations, full-wave and half-wave rectifiers, and Zener diode voltage regulation.
- Operational Amplifiers & Integrated Circuits: Inverting and non-inverting amplifier configurations, open-loop vs closed-loop gain, and comparator applications.
- Atomic Energy Transitions & Lasers: Population inversion, stimulated emission, optical pumping, and characteristics of monochromatic laser light.
High-Frequency Sample MCQs for Practice
Test your understanding with these representative Physics MCQs frequently asked in tri-services academic tests:
1. The main difference between an intrinsic and an extrinsic semiconductor lies in its:
A) Temperature
B) Purity level and presence of dopants
C) Physical size
D) Magnetic properties
Answer: B) Purity level and presence of dopants
2. In an inverting operational amplifier, if $R_{\text{in}} = 10\ \text{k}\Omega$ and $R_f = 100\ \text{k}\Omega$, the voltage gain ($A_v$) is equal to:
A) $+10$
B) $-10$
C) $-100$
D) $+100$
Answer: B) $-10$
3. A Zener diode is specially designed to operate under which biasing condition?
A) Forward bias
B) Reverse breakdown region
C) Zero bias
D) Unbiased thermal equilibrium
Answer: B) Reverse breakdown region
4. The essential condition for producing a stimulated emission process in a laser is:
A) Thermal equilibrium
B) Population inversion
C) Spontaneous decay
D) Photoelectric absorption
Answer: B) Population inversion
5. What is the efficiency of a full-wave bridge rectifier circuit theoretically close to?
A) 40.6%
B) 81.2%
C) 50.0%
D) 100.0%
Answer: B) 81.2%
6. Electromagnetic waves carry which of the following physical quantities as they propagate?
A) Charge only
B) Mass only
C) Energy and momentum
D) Electric charge and mass
Answer: C) Energy and momentum
7. An n-type semiconductor material carries a net electrical charge of:
A) Positive
B) Negative
C) Neutral
D) Variable
Answer: C) Neutral
Detailed Overview of Physics Initial Test 8 Preparation
Preparing for Physics Initial Test 8 requires a clear understanding of electronic circuitry, semiconductor behavior, and wave physics. In military selection centers, the computer-based Physics exam evaluates both theoretical clarity and quick problem-solving ability under strict time limits. Regular practice with structured practice modules sharpens your calculation speed, improves formula recall, and guarantees peak test-day performance.
Effective Revision Tips for Test 8
- Master Op-Amp Gain Equations: Memorize inverting ($A_v = -R_f / R_{\text{in}}$) and non-inverting ($A_v = 1 + R_f / R_{\text{in}}$) operational amplifier formulas.
- Understand Semiconductor Neutrality: Remember that despite having majority free electrons, n-type materials remain electrically neutral overall.
- Practice Timed Quizzes: Solve practice questions rapidly to build optimal time management skills under real testing conditions.
Useful Resources & Next Steps
- Main Hub: Access All Forces Academic Online Quizzes
- Official Websites:
Physics Academic Test Preparation: Electromagnetism & Induction
Magnetic Forces, Ampere’s Law, Faraday’s Law & Lenz’s Law
Electromagnetism links electricity and magnetism, revealing how moving charges create magnetic fields and how changing magnetic fluxes induce electromotive force (EMF). Initial military entrance exams test candidate proficiency in magnetic force on moving charges (Lorentz force), Ampere’s law, Faraday’s law of induction, Lenz’s law, and self/mutual induction. Mastering these concepts ensures you tackle magnetic induction problems with confidence.
Lenz’s Law is a direct consequence of the law of conservation of energy; the induced current always flows in such a direction as to oppose the very cause producing it.
Major Topics Covered in Physics Quiz 9
- Magnetic Force on Moving Charges: Lorentz force equation ($F = q(E + v \times B)$) and circular motion of charged particles in uniform magnetic fields.
- Magnetic Field of Currents: Biot-Savart Law and Ampere’s Circuital Law applied to long straight wires, solenoids, and toroids.
- Faraday’s Law of Electromagnetic Induction: Induced EMF magnitude ($E = -N \frac{\Delta \Phi_B}{\Delta t}$) and flux linkage calculations.
- Inductance: Self-inductance ($L$) and mutual inductance ($M$), energy stored in magnetic fields of inductors ($U = \frac{1}{2}LI^2$).
Electromagnetic Equations
- Magnetic Force: $F = qvB\sin\theta$
- Radius in Magnetic Field: $r = \frac{mv}{qB}$
- Inductor Stored Energy: $U = \frac{1}{2}LI^2$
Proceed to Physics Quiz 9 below to test your knowledge on magnetic forces and electromagnetic induction laws.