Physics Mid Exam Syllabus (Units 1–6): Properties of Matter to Engineering Materials: 26 MCQs with answers

Hooke's law

Hooke's law gives stress ∝ strain within the elastic limit, with the constant of proportionality being the modulus of elasticity.

Elastic behaviour

Elastic behaviour means the body regains its original shape and size once the deforming force is removed, which is the regime where Hooke's law applies.

Strain

Strain is a ratio of two lengths (change in length ÷ original length), so it has no unit. Stress and the moduli are measured in N/m² or Pa.

Increases the moment of inertia about the neutral axis

The I-shape puts material in the flanges far from the neutral axis, raising the moment of inertia I. Since depression is inversely proportional to I, the beam bends less for the same load and mass.

Rigidity modulus

The period T = 2π√(I/C) gives the couple per unit twist C, and C = πηr⁴/(2l) then yields the rigidity modulus η of the wire material.

Proportional to displacement and directed towards the mean position

SHM is defined by F = −kx: the force is proportional to displacement and always directed back towards the mean position.

Diffraction of sound in air

The syllabus names blackbody radiation, the photoelectric effect and the Compton effect as the classical failures. Sound diffraction is a classical wave phenomenon and is not one of them.

$\lambda = h/(mv)$

The de Broglie hypothesis states λ = h/p, and for a particle of momentum p = mv this becomes λ = h/(mv).

Davisson-Germer experiment

Davisson and Germer observed electron diffraction from a nickel crystal, confirming the de Broglie matter-wave hypothesis.

$-(\hbar^2/2m)\,d^2\psi/dx^2 + V\psi = E\psi$

The time-independent form has no time derivative and gives stationary states with definite energy E. The option containing ∂ψ/∂t is the time-dependent form.

Spontaneous emission

A₂₁ is the probability coefficient for spontaneous emission, while B₁₂ and B₂₁ describe absorption and stimulated emission respectively.

Makes stimulated emission exceed absorption, giving amplification

With more atoms in the upper state than the lower state, stimulated emission dominates over absorption, so light is amplified rather than absorbed.

Complete expulsion of magnetic flux from a superconductor

Below the critical temperature a superconductor behaves as a perfect diamagnet, expelling all magnetic flux so that B = 0 inside it.

Type II

Type II superconductors have two critical fields and permit flux to penetrate as vortices between them, which lets them carry higher currents and be used in strong magnets.

Holes

P-type material is doped with trivalent impurities that create holes, so holes are the majority carriers; electrons are the minority carriers.

True

The Physics mid-exam date is 29-09-2026, and the exam window runs from 28 September to 5 October 2026.

Stress is directly proportional to strain.

According to Hooke's law, within the elastic limit, stress is directly proportional to strain, which is expressed as \( \sigma = E \epsilon \), where \( \sigma \) is stress, \( E \) is Young's modulus, and \( \epsilon \) is strain.

Young's modulus is a measure of a material's stiffness.

Young's modulus quantifies the stiffness of a material; a higher value indicates a stiffer material, while a lower value indicates a more flexible material.

Rigidity modulus of the wire

The time period of a torsional pendulum is used to determine the rigidity modulus of the wire, which relates to how the material resists twisting.

Energy is quantized and not continuous.

The photoelectric effect shows that light can behave as both a wave and a particle, and that energy is quantized, contradicting classical physics which assumes continuous energy transfer.

Superconductors expel magnetic fields completely.

The Meissner effect refers to the phenomenon where superconductors expel magnetic fields when they transition into the superconducting state, demonstrating perfect diamagnetism.

$$\delta = \frac{PL^3}{3EI}$$

The correct formula for the deflection of a cantilever beam under a point load at the free end is given by $$\delta = \frac{PL^3}{3EI}$$, where I is the moment of inertia of the beam's cross-section.

$$G = \frac{\pi^2 mL}{T^2 r^4}$$

The correct relationship for determining the rigidity modulus (G) in a torsional pendulum is $$G = \frac{\pi^2 mL}{T^2 r^4}$$, where m is the mass of the pendulum.

Kinetic energy is directly proportional to frequency minus the work function.

In the photoelectric effect, the kinetic energy (KE) of emitted electrons is given by the equation $$KE = hf - \phi$$, where $$hf$$ is the energy of the incident photons and $$\phi$$ is the work function.

The total energy is halved.

The total mechanical energy in SHM is given by $$E = \frac{1}{2} k A^2$$, where A is the amplitude. Halving the amplitude reduces the energy by a factor of four, so the energy is halved when considering the new amplitude.

It allows partial magnetic field penetration between two critical fields.

Type II superconductors allow partial penetration of magnetic fields between two critical magnetic field strengths, thus exhibiting unique magnetic behavior compared to Type I superconductors.