BTEC Applied Science Level 3 Unit 3: Principles and Applications of Physics Assessment Answers

BTEC Applied Science Level 3 Unit 3 Summary

Level: 3
Unit type: External
Guided learning hours: 60

Unit in brief

Students will explore the use of practical and mathematical skills in the study of waves.
motion and electricity.

Unit introduction

If you have ever thought about how a car works or how circuitry works, the common answer you should have got is ‘it's because of Physics’. Physics plays a big part in everything you see around yourself; even throwing a stone in a lake is physics. In this unit, you will explore the role that physics plays in our daily activities, communication networks, and our work with electrical circuits and tasks. 

In this unit, students will deal with how electromagnetic waves have become the basis of today’s modern communication systems. Wifi, Bluetooth, and mobile phones are among the concepts that you are familiar with. This unit will help you understand how these systems work and how their activities are performed. Laws of motion and overall study of motion are also a big part of this unit, as here you will also develop an understanding of how safety products for our everyday lives are made using the study of motion. Crumple zones, airbags, and seatbelts are among the most common innovations that came through the study of motions. As the use of electrical devices has recently which shows that it will rise more in future for that understaning electrical circuits, electricity and their relationships with energy usage. With the help of physics, even you will be able to create alternatives for energy, which can help you in developing greater sustainability in future. 

Learning practical investigation, physical principles and mathematical skills through this unit will help you in higher levels and even at the place you work. Understanding concepts from this unit will help you if you are looking forward to professional qualifications like nursing, social care, health and technicians in medicine, laboratry and dentistry quality control.

AO1 Demonstrate knowledge and understanding of scientific concepts and theories, terminology, definitions and scientific formulae used in Physics.

Answer:

In order to achieve this assessment outcome, the students should be able to represent a clear image of the basic principles of physics, correctly use the scientific terms, and remember important formulae. This contains the knowledge in fields like waves, motion, the laws of Newton, electric circuits and transfer of energy as indicated in the unit specification.

Waves and a Guide to Wave Terms

The students are supposed to be able to define and explain the main terms related to waves, like periodic time, speed of the wave, wavelength, frequency, amplitude and oscillation.
The wave equation gives the relationship between the properties of waves:

•  v = fλ
•  v is the speed of the wave, f is the frequency and 1 wavelength.

Students should also be familiar with the comparison and contrast of the transverse waves versus the longitudinal waves, notions of displacement, phase difference, path difference, coherence, superposition, when used in a diffraction grating, as well as with line emission spectra.

Moreover, to learn about communication systems like satellite communication, Wi-Fi, Bluetooth, infrared, and mobile phones, one should know that the electromagnetic waves move at the speed of light in a vacuum, their locations in the electromagnetic spectrum, and in what areas they exist.

Optical fibres are governed by the principles as follows

Students should be able to explain what refraction and total internal reflection (TIR) are and what the circumstances of this effect are, that is, when the light ray is moving through a material that is more optically dense, as well as when the angle of incidence is greater than the critical angle.

Defining The refractive index is defined by:

• n = c / v
• and can also be expressed as:
• sin i / sin r
• One can determine the critical angle as follows:
• sin C = 1 / n

Knowledge of the impact of cladding on the optical fibre critical angle is significant in understanding the processes of transmitting light signals through communication systems in an efficient manner.
Forces and Newton's Laws of Motion
The students should be able to know standard SI units and symbols of initial velocity (u), final velocity (v), displacement (s), time (t), and acceleration (a).

The important laws of motion are:

• v = u + at
• s = ut + ½at²
• v² = u² + 2as
• s = (u + v)t / 2

It is necessary to understand scalar quantities that include distance and vector quantities that include velocity when reading displacement-time graphs and velocity-time graphs.

Students should also learn the first, second, and Third Laws of Motion by Newton and the equation:

• F = ma
• and momentum:
• p = mv

It is also necessary to know inertia, mass, weight, and strength of a gravitational field (g) with the equation:

• W = mg

Electrical Circuits and Electrical Quantities

Students need to be capable of defining and applying terms like current, potential difference, power, energy, and resistance, as well as their units:

• Current in amps (A)
• V 2 -V 1 V volt-volt difference
• V volt-volt difference.
• Power in watts (W)
• Energy in joules (J)
• Resistance in ohms (Ω)

Key equations include:

• V = IR
• P = IV
• P = E / t
• E = VIt

Students should be made aware of the role of the elements like resistors, variable resistors, diodes, thermistors, light-dependent resistors (LDRs), photodiodes, and LEDs.

Energy and Thermodynamics Physics

The students should know how to transfer energy and change temperature with the help of:
ΔQ = mcΔT
where:
•    m = mass
•    c = specific heat capacity
•    ΔT = temperature change

They should also be able to know certain latent heat of fusion and vaporisation by using:
ΔQ = mL

There should be knowledge of units of energy like joules (J), kilojoules (kJ), and megajoules (MJ) and the capability to change between Celsius (degrees C, or C) and Kelvin (K).

To demonstrate AO1 in Physics, one has to be able to accurately define terms, recall scientific equations and laws, and demonstrate good knowledge of concepts connected with waves, optical fibres, motion, the Laws of Newton, electrical circuits and the transfer of energy. This background knowledge is a foundation on which additional application and analytical skills are needed in higher assessment outcomes.

AO2 Apply knowledge and understanding of scientific concepts and theories, procedures, processes and techniques in Physics.

Answer:

In order to obtain this assessment outcome, students should go further than memorising definitions and be able to show that they can apply the principles of physics to real-life situations, calculations, and scenarios. This is through the correct use of formulae, interpretation of any graphical data, use of laws of motion and how physics is utilised in communication systems, transportation and transfer of energy.

Using Wave Principles and the Wave Equation

Students use their knowledge of the properties of waves in solving the wave equation (v = f 1 2 ) to find the speed of a wave (v ), frequency (f ), or wavelength ( 1 2 ) when they know two values. As an example, when the frequency of a signal involved in Wi-Fi or satellite communication is known, students are able to use it to determine the wavelength and the relationship between this and the transmission of signals.

In real life, students use their knowledge about transverse waves and longitudinal waves in differing between the electromagnetic waves and sound waves. They can also read graphs of waves, deduce amplitude, wavelength and periodic time using diagrams.

Discussing the subject of diffraction gratings, students use the concepts of superposition, path difference, and phase difference to explain how line emission spectra come into being. The application is especially crucial in determining the elements in gases through the study of their emission lines, which connects the theory and the laboratory and industrial methods.

Use of Principles of Optical Fibres

Optical fibre. The refraction and total internal reflection (TIR) knowledge is used to analyse the characteristics of optical fibre in terms of their ability to transmit data effectively. Students compute the critical angle by using the formula refractive index (n = c / v) or, because sin C = 1/n, the formula sin C = 1/n to find the critical angle at an interface between the glass and the air.

They use this knowledge to explain the purpose of using cladding in optical fibres. Total internal reflection is ensured by making sure that the refractive index of the cladding is lower than that of the core so that the signal is not lost. This shows the way theoretical physics contributes to the real-world communication channel, like mobile communication, Bluetooth © and infrared transmission.

The use of Newton's Laws and Equations of Motion

The First, Second and Third Laws of Motion are used by the students to study the forces during transportation or during normal motion. They use the equation F = ma to determine the force that is needed in order to accelerate an object with known mass. This enables them to understand the effect of a change of mass or acceleration on force.

The SUVAT equations are used when students solve motion problems, e.g.:
•    v = u + at
•    s = ut + ½at²
•    v² = u² + 2as

They also use velocity-time graphs, the gradient of which is acceleration, and the area under which is displacement. Through the study of such graphs, students will be able to know whether an object moves at a constant velocity, accelerates or decelerates.

Students use their knowledge of momentum (p = mv) and impulse to discuss the safety aspects of airbags, seat belts, and crumple zones in a transportation setting. These devices prolong the duration over which the momentum varies, thereby lowering the force on one during a collision.

Using Principles of Electricity Circuits

The equations that are used to apply the student to know about electrical relationships are:
•    V = IR
•    P = IV
•    E = VIt

Considering the example, they compute the amount of current through a circuit when resistance and potential difference are known. They can also find the power rating of domestic appliances and compute the amount of energy transferred in kilowatt-hours (kWh = kW × h) when looking at domestic electricity consumption.

It is also used in the selection of the correct components, including resistors, variable resistors, thermistors, light-dependent resistors (LDRs), and LEDs to specific circuit designs. Students learn to put the ammeters in series, voltmeters in parallel, so that the measures of current and potential difference are correct.

This is an indication of feasible knowledge of electrical measurement skills and safe circuit design.

Being able to use Energy Transfer and Thermal Physics

Students apply the equation:
•    ΔQ = mcΔT
to find the amount of energy it takes to change the temperature of a substance. They can, as an example, estimate the amount of energy required to heat water in a domestic appliance, or estimate the amount of heat a material can hold in a given experiment.

In the analysis of the change of state, students employ:
•    ΔQ = mL

to determine the latent heat of fusion or vaporisation that is specific. This will enable them to give reasons why the temperature does not change during melting or boiling, although power is applied to it.

Students also convert between Celsius (o C) and Kelvin (K) where necessary, which is procedural correctness when calculating thermal energy.
The application of the Inverse Square Law

Students use the inverse square law (I = k / r 2) in the contexts of communication and wave intensity to explain the reduction in the intensity of waves as a function of distance. This is more so when examining the strength of the signal in the satellite systems and the reason why transmitters should be at a strategic position.

In Physics, students need to display AO2 by using formulae, laws, and theory to solve any practical problems, as well as experimental and real-world data. Students demonstrate that they can apply physics as a working tool rather than a memorising tool when using Newton Laws, velocity versus time graphs, energy transfer equations where ΔQ = mcΔT and when discussing the total internal reflection in optical fibres.
This is an outcome of having confidence in using knowledge about physics in analogous, mathematical and technological contexts.

AO3 Analyse and interpret scientific information in Physics.

Answer:

In order to achieve this outcome of assessment, students should be able to analyse data, identify patterns and relationships, and determine the reasons and conclusions based on the principles of physics. And it is more than working with equations; it involves analysing facts, justifying patterns, and even connecting observations with accepted scientific theory.

Study of Wave Behaviour and Graphical Representations

The students decompose scientific knowledge about the waves, understanding the diagrams and graphical data. Given wave diagrams, they recognise the characteristics of amplitude, wavelength, frequency, and periodic time and how these characteristics influence energy transfer.

With the wave equation (f 1 f 2 = v 1 v 2 1 ), students can explain how wavelength changes as frequency changes when the speed of waves is held constant. An example is where they can explain why the higher the frequency of communication systems, e.g. Wi-Fi, Bluetooth © or satellite communication, the shorter the wavelength and the impact this has on the behaviour of the signal.

In the case of the analysis of experimental data concerning diffraction gratings, students are to interpret line emission spectra to determine elements in gases. Through studying the pattern of emission lines and correlating them with the change of the electron energy levels in the atom, students will be able to defend their capability to analyse the spectral data instead of describing it in a scientific way.

Optical Fibre Performance Interpretation

With respect to optical fibres, students study the effect of refraction and total internal reflection (TIR) on the transmission of signals. On receiving numerical values, they obtain values of refractive index (n = c / v) to compute the critical angle by the equation sin C = 1/ n.

The angle of incidence and refractive index can be used to make students judge whether total internal reflection will take place. They also derive the impact of cladding on the performance of optical fibres in terms of minimising the signal losses. This demonstrates an appreciation of the fact that theoretical calculations can be used in effective communication technology.

The Graphical Data Analysis

One of the skills of analysis in physics is the interpretation of displacement-time graphs and velocity-time graphs. Students are supposed to get out such information as velocity, as the gradient of a displacement-time graph, or acceleration, as the gradient of a velocity-time graph.
In the study of velocity-time charts, the students find the displacement by finding the area beneath the chart. They also understand whether motion is constant velocity, uniform acceleration or deceleration.

Applying the SUVAT equations, such as:
•    v = u + at
•    v² = u² + 2as

Students compare graphical interpretations and mathematical calculations, which makes their conclusions more valid.
Comparison of Forces and Newton's Laws in Practical Situations

Students examine situations that deal with the First, Second, and Third Laws of Motion identified by Newton in order to understand the influence of forces on motion. With F = ma, they describe how variation in either mass or acceleration varies the force requirements.

In examining the transportation safety systems like airbags, seat belts, and crumple zones, students explain that the longer the impact period, the less force there will be, due to the dispersion of an increase in momentum change over a greater time period. This is directly related to momentum (p = mv) and the change of momentum with time.

There are also situations analysed by students, which involve air resistance, drag and terminal velocity, how the forces finally become equal, and the acceleration is reduced to zero. This corresponds to the knowledge of resultant force and equilibrium states.
Electrical Circuit Data Interpretation

In electrical systems, equations such as these are analysed by the students.
•    V = IR
•    P = IV
•    E = VIt
They reason whether measurements given in an experiment obey the Ohm Law or are evidence of a circuit behaviour anomaly. Indicatively, through the study of the variation of resistance in a thermistor or light-dependent resistor (LDR), students can understand how temperature or light intensity varies the current flow.

The domestic energy usage is also examined as students interpret the ratings of power and calculate the energy transmitted (kWh = kW × h). They assess the effect of design and the use patterns of appliances on the overall energy consumption.

Transfer of Energy and Thermal Processes

In the analysis of thermal experiments, the students use the equation below to explain the temperature change:
•    ΔQ = mcΔT

They compare the consistency of the results with the expected specific heat capacity values and take into consideration the possible errors, including heat loss to the surroundings.

During changes of state, they understand why temperature does not change as energy is still put in, by using:
•    ΔQ = mL

In this analysis, the difference between the change in temperature and the change in phases and the knowledge of the specific latent heat of fusion and vapourisation is demonstrated.

The students are also able to understand energy values in joules (J), kilojoules (kJ), megajoules (MJ) and interchange between energy units where needed to draw the right conclusions.

The use of the inverse square law in Communication

The students evaluate the intensity of waves against the distance through the inverse square law (I = k / r 2 ). They use the observation of data sets that exhibit a decrease in intensity with distance to explain why communication signals become weaker and why it is relevant to place transmitters where important. This discussion relates the theoretical relationship to engineering decisions in practice.    

Making Bonafide Scientific Conclusions

One of the major components of AO3 is the ability to make evidence-based conclusions. Students should be able to make logical interpretations of the data, be able to connect the explanations to physics concepts directly, and be able to decide whether the results received are realistic or are caused by measurement errors.

The students can think at a higher level, whether it is analysing the properties of waves, the Laws of Electricity, or transfer of thermal energy by identifying patterns, making explanations and justifying their claims using the right formula and vocabulary.

To show AO3 in Physics, students need to analytically interpret scientific data, understand data in graphs and numbers, and make justified conclusions based on the accepted rules, including: v = f 3, F = ma, V = IR, and 8Q mc 8T. This result shows that a student is capable of thinking scientifically, analysing facts, and using the knowledge of physics to solve complex and uncommon cases.