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The microwaves from the transmitter T are vertically polarised and have a wavelength of about 3 cm - AQA - A-Level Physics - Question 2 - 2021 - Paper 1
Question 2
The microwaves from the transmitter T are vertically polarised and have a wavelength of about 3 cm. Figure 1 shows apparatus used to investigate the properties of m... show full transcript
Worked Solution & Example Answer:The microwaves from the transmitter T are vertically polarised and have a wavelength of about 3 cm - AQA - A-Level Physics - Question 2 - 2021 - Paper 1
Step 1
Deduce whether this practical arrangement is suitable for a determination of a value for the wavelength.
Answer
To determine if this practical arrangement is suitable for measuring the wavelength of the microwaves, consider:
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Wavelength Context: Given that the wavelength is approximately 3 cm, any measurement should ideally be made with a path or separation that is a significant fraction of this value to achieve accurate results.
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Distance Measurements: The distances involved in the setup (2m apart) suggest that path differences not exceeding the wavelength will yield meaningful interference patterns.
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Conclusion: Since the apparatus can measure path lengths of about 3 cm or greater, the practical setup is indeed suitable to accurately determine the wavelength of the microwaves, ensuring that refinements in the distance adjustments offer consistent patterns to observe.
Step 2
Suggest why Young's double-slit equation should not be used to determine the wavelength.
Answer
Young's double-slit equation may not be suitable for determining the wavelength in this scenario due to the following reasons:
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Grating Slit Separation: The slit separation being greater than the wavelength could lead to inappropriate assumptions in the interference pattern observed, leading to inaccurate wavelength calculations.
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Diffraction Effects: Significant diffraction effects may distort the expected patterns, particularly if the light source does not provide a monochromatic output.
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Measurement Precision: The need for precise measurement of fringe separation and screen distance may not be met under the current arrangements, pressuring the reliability of utilizing the double-slit equation for wavelength determination.