FAD1022 UAS 2024-2025

Basic Physics II Final Examination (Peperiksaan Akhir Semester / Ujian Akhir Semester) for 2024/2025 Semester 2 at Universiti Malaya PASUM.

Exam Information

  • Course: FAD1022 - Basic Physics II (Fizik Asas 2)
  • Academic Year: 2024/2025
  • Semester: 2
  • Date: Mei/Jun 2025 (May/June 2025)
  • Duration: 3 hours (Masa: 3 jam)
  • Total Questions: 26 questions across 23 printed pages
  • Format:
    • Section A: Answer ALL 15 questions (3 marks each, except where noted)
    • Section B: Answer THREE out of five questions (12 marks each)
    • Section C: Answer FOUR out of six questions (12 marks each)

Constants Provided (Pemalar)

Constant Symbol Value
Mass of proton $m_p$ $1.007276 \text{ u} = 1.67 \times 10^{-27} \text{ kg}$
Permittivity of free space $\varepsilon_0$ $8.85 \times 10^{-12} \text{ F m}^{-1}$
Permeability of free space $\mu_0$ $4\pi \times 10^{-7} \text{ T m A}^{-1}$
Mass of electron $m_e$ $9.11 \times 10^{-31} \text{ kg}$
Mass of neutron $m_n$ $1.008665 \text{ u}$
Electron charge $e$ $-1.60 \times 10^{-19} \text{ C}$
Speed of light $c$ $3.0 \times 10^{8} \text{ m s}^{-1}$
Planck's constant $h$ $6.63 \times 10^{-34} \text{ J s}$
1 atomic mass unit $1 \text{ u}$ $931.5 \text{ MeV c}^{-2}$
Coulomb's constant $k$ $9 \times 10^{9} \text{ N m}^2 \text{ C}^{-2}$

Formulas Provided

  1. $Q = CV$
  2. $U = \frac{1}{2}CV^2$
  3. Series connection: $\frac{1}{C_{eq}} = \frac{1}{C_1} + \cdots + \frac{1}{C_n}$
  4. Parallel connection: $C_{eq} = C_1 + \cdots + C_n$
  5. Energy: $E = \Delta mc^2$
  6. Heisenberg uncertainty: $\Delta x \cdot \Delta p \geq \frac{h}{4\pi}$
  7. Momentum: $p = mv$

Unit Conversion

$$1 \text{ eV} = 1.602 \times 10^{-19} \text{ J}$$

Question Breakdown

Section A — Answer ALL Questions

Question A1 (3 marks)

  • Topic: Electrostatics — Coulomb's Law
  • Concepts: Coulomb's Law, Electrostatic Force
  • Question: Explain how the electrostatic force between two charges changes if:
    • (a) the distance between charges is decreased to half
    • (b) magnitude one of the charges is doubled

Question A2 (3 marks)

  • Topic: Electrostatics — Electric Potential
  • Concepts: Electric Potential, Superposition Principle
  • Question: Two isolated point charges $q_1 = +3.6 \text{ }\mu\text{C}$ and $q_2$ are separated by distance $AB = 50 \text{ cm}$. Point $P$ is located $20 \text{ cm}$ from $q_1$. If the electric potential at $P$ is zero, calculate the value of $q_2$.
  • Diagram: Linear arrangement with charges on axis, P between them (closer to $q_1$)

Question A3 (3 marks)

  • Topic: Capacitors & Dielectrics — Parallel Plate Capacitor
  • Concepts: Capacitance, Parallel Plate Capacitor, Dielectric
  • Question: A parallel-plate capacitor has plates of area $A = 0.35 \text{ m}^2$ separated by $d = 10 \text{ mm}$ and is filled with dielectric material. If the dielectric constant is $\kappa = 5.5$, calculate the capacitance.

Question A4 (3 marks)

  • Topic: DC Circuits — Ohm's Law
  • Concepts: Ohm's Law, Terminal Voltage
  • Question: Calculate current in the circuit if the voltmeter reading is $8.8 \text{ V}$. The circuit shows a battery with voltmeter across it and resistor $R = 10 \text{ }\Omega$ in series.
  • Diagram: Simple series circuit with battery, voltmeter parallel to battery, and $10 \text{ }\Omega$ resistor

Question A5 (3 marks)

  • Topic: AC Circuits — Capacitive Reactance
  • Concepts: Capacitive Reactance, RMS Values, AC Current
  • Question: A capacitor with capacitive reactance $X_C = 60 \text{ }\Omega$ is connected to an alternating current $I(t) = 2.5 \sin(100\pi t)$. Determine the root mean square (rms) voltage.

Question A6 (3 marks)

  • Topic: AC Circuits — Resonance
  • Concepts: Resonance, Series RLC Circuit, Inductive Reactance, Capacitive Reactance
  • Question: Determine the value of capacitor required in series with a resistor and an inductor of $L = 2.0 \text{ H}$ to ensure the current is in phase with the supply voltage of $240 \text{ V}$, $50 \text{ Hz}$.

Question A7 (3 marks total)

  • Topic: Magnetism — Velocity Selector & Torque on Current Loop
  • Concepts: Lorentz Force, Velocity Selector, Torque on Current Loop
  • Question (a) (1 mark): A charged particle moves without any deflection inside a region containing both magnetic and electric fields. Identify the underlying concept of the motion of the charged particle.
  • Question (b) (2 marks): Figure A7(b) shows a coil carrying a constant current placed horizontally (H) and vertically (V) in a uniform magnetic field. Determine which configuration will produce (i) zero torque, (ii) maximum torque.
  • Diagram: Two configurations of coil between N-S magnets — horizontal (H) and vertical (V) orientations

Question A8 (3 marks)

  • Topic: Magnetism — Mass Spectrometer
  • Concepts: Mass Spectrometer, Circular Motion in Magnetic Field, Lorentz Force
  • Question: A charge $q = 6.4 \times 10^{-18} \text{ C}$ moves with speed $v = 1.5 \times 10^{6} \text{ m s}^{-1}$ through a velocity selector and hits point $P$ in the mass selector. Calculate the mass of the charge if radius $r = 2.8 \text{ mm}$ and magnetic field in the mass selector is $B = 1.6 \text{ T}$.
  • Diagram: Velocity selector with E and B fields, followed by semicircular path in mass selector

Question A9 (3 marks)

  • Topic: Electromagnetic Induction — Lenz's Law
  • Concepts: Lenz's Law, Induced Current, Magnetic Poles
  • Question: A bar magnet is brought closer to a loop of wire. From the observer's point of view, determine:
    • (a) pole of loop
    • (b) direction of induced current
    • (c) physics law in this case
  • Diagram: Bar magnet (N-S vertical) approaching circular wire loop with resistor

Question A10 (3 marks)

  • Topic: Electromagnetic Induction — Motional EMF
  • Concepts: Motional EMF, Faraday's Law
  • Question: A wire of length $l = 0.2 \text{ m}$ moves with uniform velocity $v = 0.5 \text{ m s}^{-1}$ perpendicular to magnetic field $B = 4 \text{ T}$. Calculate the induced electromotive force in the wire.

Question A11 (3 marks)

  • Topic: Inductance & Transformers — Transformer
  • Concepts: Transformer, Turns Ratio
  • Question: The current produced in the secondary coil of a transformer is $I_s = 0.4 \text{ A}$ when the current in the primary coil is $I_p = 6.0 \text{ A}$. Calculate the primary turns if the secondary turns is $N_s = 450$.

Question A12 (3 marks total)

  • Topic: Semiconductors & Diodes — Diode Characteristics
  • Concepts: Diode, Forward Bias, Temperature Effects
  • Question (a) (2 marks): Describe how an increase in temperature affects the forward bias knee curve of a silicon diode.
  • Question (b) (1 mark): Sketch the output waveform across the diode in a series circuit containing an AC power supply, a resistor, and a Si diode.

Question A13 (3 marks)

  • Topic: Operational Amplifiers — Non-inverting Amplifier
  • Concepts: Operational Amplifiers, Non-inverting Amplifier, Voltage Gain
  • Question: A non-inverting operational amplifier produces an output voltage $V_o = +15 \text{ V}$. If the feedback resistor $R_f = 800 \text{ k}\Omega$ and input resistor $R_1 = 200 \text{ k}\Omega$, calculate the required input voltage $V_{in}$.

Question A14 (3 marks)

  • Topic: Nuclear Physics — Radioactive Decay
  • Concepts: Radioactive Decay, Decay Constant, Half-life
  • Question: The radioisotope Iodine-131 is used to treat overactive thyroid glands. Calculate the decay constant of Iodine-131 if its half-life is 8 days. Give your answer in SI unit.

Question A15 (3 marks)

  • Topic: Modern Physics — Electron Acceleration
  • Concepts: Electron Acceleration, Kinetic Energy, Momentum
  • Question: An electron is accelerated from rest through a potential difference of $150.0 \text{ V}$. Calculate the momentum of the electron.

Section B — Answer THREE Questions (12 marks each)

Question B1 (12 marks)

  • Topic: Electrostatics — Electric Field & Electron Deflection
  • Concepts: Electric Field, Spherical Conductor, Electron Motion
  • Question (a) (2 marks): Explain how the electric field strength changes when the distance from a point charge is doubled.
  • Question (b) (4 marks): A spherical conductor with radius $r = 50 \text{ cm}$ carries charge $Q = +25 \text{ }\mu\text{C}$. Given $OA = 20 \text{ cm}$ and $OB = 70 \text{ cm}$ from center, determine the electric field strength at point (i) A, (ii) B.
  • Question (c) (6 marks): An electron travelling at speed $v = 1.5 \times 10^{7} \text{ m s}^{-1}$ enters between two parallel metal plates. Time taken is $t = 4.0 \times 10^{-9} \text{ s}$, plate length $60 \text{ mm}$, separation $20 \text{ mm}$. Electric field is $E = 4.5 \times 10^{3} \text{ V m}^{-1}$. Calculate the velocity and deflection angle when it emerges (gravitational acceleration negligible).
  • Diagram: Parallel plates with electron entering horizontally, E-field pointing downward

Question B2 (12 marks)

  • Topic: Capacitors & Dielectrics — Capacitor Circuits
  • Concepts: Capacitor Energy, RC Circuit, Series Capacitors
  • Question (a) (2 marks): Identify how to increase the number of charges that can be held by a parallel plate capacitor if the voltage is fixed.
  • Question (b) (4 marks): A fully charged capacitor has $C = 12.0 \text{ }\mu\text{F}$ and charge $Q = 6.0 \text{ mC}$. The capacitor discharges through $R = 100 \text{ }\Omega$. Calculate the time taken to discharge if only 20% charge is left.
  • Question (c) (6 marks): Two capacitors $C_1 = 12 \text{ }\mu\text{F}$ and $C_2 = 4 \text{ }\mu\text{F}$ are connected in series to a $24 \text{ V}$ battery. Calculate the energy stored in capacitor $C_1$.
  • Diagram: Two capacitors in series with battery

Question B3 (12 marks)

  • Topic: DC Circuits — Circuit Analysis
  • Concepts: Voltage Divider, Kirchhoff's Laws, Wheatstone Bridge
  • Question (a) (2 marks): After load is connected to the circuit, state the change in potential difference across (i) resistor $R_1$, (ii) resistor $R_2$.
  • Question (b) (4 marks): If $R_1 = 3.0 \text{ }\Omega$, $R_2 = 6.0 \text{ }\Omega$, $R_3 = 3.0 \text{ }\Omega$, $R_4 = 3.0 \text{ }\Omega$ with $\varepsilon = 12 \text{ V}$, calculate the output voltage at point A.
  • Question (c) (6 marks): Determine voltage drop across resistor $R_1$ in the given circuit with $R_1 = 3000 \text{ }\Omega$, $R_2 = 2000 \text{ }\Omega$, $R_3 = 3000 \text{ }\Omega$, $R_4 = 2000 \text{ }\Omega$, $R_5 = 4000 \text{ }\Omega$ (Wheatstone bridge configuration), $\varepsilon = 12 \text{ V}$.
  • Diagram: Bridge circuit with resistors forming diamond shape

Question B4 (12 marks)

  • Topic: AC Circuits — Phasors & Reactance
  • Concepts: Phasor Diagram, Capacitive Reactance, Inductive Reactance
  • Question (a) (2 marks): Sketch the phasor diagram representing pure inductive circuit and pure capacitive circuit.
  • Question (b) (4 marks): Determine the rms current if $10 \text{ V}$, $50 \text{ Hz}$ AC supply is connected separately to (i) capacitor with $X_C = 5.79 \text{ }\Omega$, (ii) inductor with $X_L = 3.14 \text{ }\Omega$.
  • Question (c) (6 marks): The value of capacitive reactance at $f = 45 \text{ Hz}$ is $X_C = 11.3 \text{ }\Omega$.
    • (i) Calculate the new $X_C$ if frequency is doubled.
    • (ii) Explain the change and state the relationship between frequency and $X_C$.

Question B5 (12 marks)

  • Topic: AC Circuits — RLC Series Circuit
  • Concepts: RLC Series Circuit, Power Factor, Impedance, Resonance
  • Question (a) (2 marks): Describe TWO conditions required for an RLC circuit to achieve a power factor of one.
  • Question (b) (4 marks): A series RLC circuit with $R = 100 \text{ }\Omega$, $C = 20 \text{ }\mu\text{F}$, $L = 0.2 \text{ H}$ is connected to AC source. The ratio of voltage across capacitor to inductor is four. Calculate the operating frequency.
  • Question (c) (6 marks): A series RLC circuit connected to $230 \text{ V}$ rms has power factor $0.85$ and average power consumption $800 \text{ W}$. Calculate the impedance of the circuit.

Section C — Answer FOUR Questions (12 marks each)

Question C1 (12 marks)

  • Topic: Magnetism — Magnetic Force & Torque
  • Concepts: Magnetic Force on Moving Charge, Torque on Current Loop, Ampere's Law
  • Question (a) (2 marks): A positive charge moves with velocity $v$ in $-x$-axis direction approaching a coil carrying current. Determine the direction of magnetic force at point $P$ (give answer using provided axis: $+x$, $+y$, $+z$).
  • Question (b) (4 marks): A rectangular loop ($0.60 \text{ cm} \times 0.30 \text{ cm}$) carrying $I = 1.5 \text{ A}$ is placed between magnet poles with $B = 0.8 \text{ T}$. Plane tilted at $25°$ to magnetic field. Determine (i) torque on loop, (ii) direction of rotation (clockwise/counterclockwise).
  • Question (c) (6 marks): A long straight wire with $I_1 = 9.0 \text{ A}$ is placed $1.5 \text{ cm}$ from a square loop ($4.0 \text{ cm}$ side) with current $I_2$. Calculate $I_2$ if resultant magnetic force on loop is $-24.5 \text{ }\mu\text{N}$.
  • Diagram: Loop between magnet poles; square loop near straight wire

Question C2 (12 marks)

  • Topic: Electromagnetic Induction — Faraday's Law
  • Concepts: Faraday's Law, Induced EMF, Motional EMF
  • Question (a) (2 marks): Identify factors that can increase the value of electromotive force (emf) in an alternating current generator.
  • Question (b) (4 marks): A coil of $N = 20$ turns, each with area $A = 50 \text{ cm}^2$, positioned perpendicular to uniform magnetic field increasing from $B_i = 2.0 \text{ T}$ to $B_f = 6.0 \text{ T}$ in $\Delta t = 2.0 \text{ s}$. Calculate magnitude of induced emf.
  • Question (c) (6 marks): Two parallel rods A and B perpendicular to magnetic field. Ends connected to resistor $R = 10 \text{ }\Omega$. Wire CD moves with uniform velocity $v = 5 \text{ m s}^{-1}$ by constant force $F = 15 \text{ N}$. Determine magnitude and direction of induced current.
  • Diagram: Two parallel conducting rails with moving rod, resistor connected between rails

Question C3 (12 marks)

  • Topic: Inductance & Transformers — Solenoid & Mutual Inductance
  • Concepts: Self-Inductance, Mutual Inductance, Energy Stored in Inductor
  • Question (a) (2 marks): Give TWO factors that can increase inductance in a solenoid.
  • Question (b) (4 marks): A secondary coil with resistance $R_s = 8.0 \text{ }\Omega$ produces induced current $I_s = 400 \text{ mA}$ when primary coil current changes in $\Delta t = 60 \text{ ms}$. If mutual inductance $M = 3.0 \text{ mH}$, calculate change in current in primary coil.
  • Question (c) (6 marks): A solenoid with length $l = 30.0 \text{ cm}$ and diameter $d = 10.0 \text{ cm}$ carries current $I = 5.0 \text{ A}$. If energy stored is $U = 200 \text{ mJ}$, calculate the number of turns of the solenoid.

Question C4 (12 marks)

  • Topic: Semiconductors & Diodes — Transistor Biasing
  • Concepts: BJT Transistor, Transistor Biasing, Saturation Current, Collector Current
  • Question (a) (2 marks): Explain (i) purpose of biasing the transistor, (ii) role of capacitor in this transistor network.
  • Question (b) (4 marks): Calculate saturation current $I_{Csat}$ for the network and explain what happens to transistor operation during saturation.
  • Question (c) (6 marks): Determine the collector current $I_C$ of the network.
  • Circuit Parameters: $V_{CC} = 15 \text{ V}$, $R_B = 330 \text{ k}\Omega$, $R_C = 1.5 \text{ k}\Omega$, $R_E = 0.5 \text{ k}\Omega$, $\beta = 50$
  • Diagram: Common-emitter NPN transistor circuit with voltage divider biasing

Question C5 (12 marks)

  • Topic: Atomic Physics & Nuclear Physics
  • Concepts: Alpha Decay, Bohr Model, Binding Energy, Nuclear Stability
  • Question (a) (2 marks): Uranium-$^{238}{92}\text{U}$ undergoes alpha radionuclide decay into Thorium-$^{234}{x}\text{Th}$. Write the complete equation.
  • Question (b) (4 marks): A hydrogen atom is excited from ground state to third excited state ($n=4$). Calculate the wavelength of the emitted photon.
  • Question (c) (6 marks): Carbon-12 and Carbon-14 have same protons but different neutrons (isotopes). Prove which is more stable.
    • Given: Mass of $^{14}_6\text{C} = 14.003241 \text{ u}$
    • Binding Energy of $^{12}_6\text{C} = 89.094 \text{ MeV}$
    • Binding energy per nucleon $^{12}_6\text{C} = 7.425 \text{ MeV/nucleon}$

Question C6 (12 marks)

  • Topic: Modern Physics — Photoelectric Effect & Heisenberg
  • Concepts: Photoelectric Effect, Work Function, Planck's Constant, Heisenberg Uncertainty Principle
  • Question (a) (2 marks): Explain TWO factors to increase kinetic energy maximum ($KE_{max}$) in photoelectric effect.
  • Question (b) (4 marks): A proton is confined within atomic nucleus of diameter $d = 1.5 \times 10^{-15} \text{ m}$. Estimate minimum uncertainty of proton's velocity based on Heisenberg Uncertainty Principle.
  • Question (c) (6 marks): In photoelectric effect experiment, stopping potential data:
Light Frequency ($\text{Hz}$) Stopping Potential (V)
$8.0 \times 10^{14}$ $0.8$
$1.2 \times 10^{15}$ $2.4$

Calculate the work function $\phi$ and Planck's constant $h$ for this experiment.

Topic Distribution Analysis

Topic Area Questions Estimated Marks
Electrostatics A1, A2, A3, B1(a), B1(b) ~20
Capacitors & DC Circuits A4, B2, B3 ~20
AC Circuits A5, A6, B4, B5 ~24
Magnetism A7, A8, C1 ~20
Electromagnetic Induction A9, A10, C2 ~15
Inductance & Transformers A11, C3 ~10
Semiconductors & Electronics A12, A13, C4 ~20
Nuclear & Atomic Physics A14, C5 ~15
Modern Physics A15, C6 ~12

Key Topics Tested

[!important] High-Yield Topics This paper emphasizes:

  1. AC Circuit Analysis — Reactance, resonance, phasors, RLC circuits
  2. Electrostatics — Coulomb's law, electric potential, field calculations
  3. Capacitor Applications — Energy storage, RC circuits, series/parallel combinations
  4. Magnetism & Induction — Lorentz force, Faraday's law, motional EMF
  5. Modern Physics — Photoelectric effect, Bohr model, nuclear stability
  6. Semiconductors — Diode characteristics, transistor biasing

Study Recommendations

  1. Master AC circuit calculations — Practice reactance, impedance, and power factor problems
  2. Understand electrostatic principles deeply — Coulomb's law variations, potential concepts
  3. Know capacitor formulas — Energy, equivalent capacitance, charging/discharging
  4. Review magnetism thoroughly — Force on charges, torque on loops, induced EMF
  5. Practice nuclear physics — Decay equations, binding energy calculations
  6. Memorize modern physics — Photoelectric equation, Heisenberg principle applications

Related

Source: FAD1022 UAS 2024-2025 examination paper (23 pages), Universiti Malaya PASUM