The electromagnetic spectrum

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Question 3
Medium

This question is about infrared (IR) radiation.

a.

It took humans a long time to discover infrared radiation. Suggest two reasons why.

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b.

Look at the information about some infrared radiation: - The wavelength of the IR radiation is 1.4 μm1.4\ \mu\text{m}1.4 μm. - The wave speed of the IR radiation is 3.0×108 m/s3.0 \times 10^8\text{ m/s}3.0×108 m/s. Calculate the frequency of the IR radiation. Use the equation: wave speed=frequency×wavelength\text{wave speed} = \text{frequency} \times \text{wavelength}wave speed=frequency×wavelength Give your answer to 2 significant figures.

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c.

The atmosphere contains greenhouse gases. This graph shows how the percentage of infrared (IR) radiation absorbed by a greenhouse gas depends on wavelength:

A line graph with the vertical y-axis labeled 'Percentage of IR radiation absorbed (%)' from 0% to 100% in steps of 10%. The horizontal x-axis is labeled 'Wavelength (\mu\text{m})' from 1.0 to 3.0 in steps of 0.2. The curve is at 0% from 1.0 to 1.6 \mu\text{m}, then increases. At 1.8 \mu\text{m}, the absorption is 20%. At 2.4 \mu\text{m}, the absorption is 70%.

Describe the difference in the transmission of IR radiation at 1.8 μm1.8\ \mu\text{m}1.8 μm and 2.4 μm2.4\ \mu\text{m}2.4 μm. Use data from the graph in your answer.

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d.

Why are greenhouse gases important for life on Earth? Use the details about IR radiation to help explain your answer.

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The electromagnetic spectrum Questions

  1. GCSE
  2. /Physics
  3. /The electromagnetic spectrum