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Speed of Light Formula:
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This calculation determines the speed of light using a microwave oven by measuring the distance between hotspots (antinodes) of the microwave standing wave and the known frequency of the microwave radiation.
The calculator uses the formula:
Where:
Explanation: In a microwave oven, standing waves are created with nodes and antinodes. The distance between hotspots (antinodes) is half the wavelength. Multiplying by 2 gives the full wavelength, and multiplying by frequency gives the speed of the wave (light).
Details: Measuring the speed of light is fundamental in physics and has applications in telecommunications, astronomy, and many technologies that rely on electromagnetic waves.
Tips: Measure the distance between melted spots in chocolate or marshmallows placed in a microwave (with turntable removed). Enter this distance in meters and the microwave frequency (typically 2450 MHz or 2.45×10⁹ Hz for most household microwaves).
Q1: Why remove the turntable in this experiment?
A: The turntable normally rotates food to ensure even cooking, but for this experiment we need stationary standing waves to measure the distance between hotspots.
Q2: What is the typical frequency of microwave ovens?
A: Most household microwave ovens operate at 2.45 GHz (2.45×10⁹ Hz), which is in the license-free ISM band.
Q3: How accurate is this method?
A: This method can provide a reasonably accurate measurement, typically within 5-10% of the accepted value of 299,792,458 m/s, depending on measurement precision.
Q4: Why does the formula multiply by 2?
A: The distance between hotspots represents half the wavelength of the microwave radiation, so we multiply by 2 to get the full wavelength before multiplying by frequency.
Q5: What safety precautions should be taken?
A: Never operate a microwave oven empty. Use microwave-safe materials like chocolate or marshmallows, and always supervise the experiment.