When analysing stellar spectra, why is the equation E = hc/λ useful?

It allows the energy of photons at specific spectral wavelengths to be calculated, which helps identify electron transitions and the elements present in a star's atmosphere.

How can astronomers determine which elements are present in a star?

By analysing the spectral lines, since each element produces a unique pattern of lines that can be used for identification.

What is a continuous spectrum and what type of object produces it?

A continuous spectrum contains all wavelengths of light with no gaps, produced by hot dense objects like the interior of stars.

OCR A-Level Physics A H556

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Absorption spectra and spectral lines

3 things to know
Papers 1, 2 and 3

Overview

Recall questions on how emission lines are produced, continuous, emission and absorption line spectra, why each element has its own line pattern, and identifying the elements in a star.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Process

In the process of emission line production, what is the initial state of the electron?

Key term

What happens to an electron during the production of an emission spectral line?

Key term

Why do different elements produce different spectral line patterns?

Questions from this subtopic

Each one with the model answer underneath.

1
In the process of emission line production, what is the initial state of the electron?
Model answer
The electron is in an excited state at a higher energy level.
2
What happens to an electron during the production of an emission spectral line?
Model answer
The electron transitions from a higher energy level to a lower energy level.
3
When analysing stellar spectra, why is the equation E = hc/λ useful?
Model answer
It allows the energy of photons at specific spectral wavelengths to be calculated, which helps identify electron transitions and the elements present in a star's atmosphere.
4
Why do different elements produce different spectral line patterns?
Model answer
Different elements have different arrangements of energy levels, producing unique spectral lines that act as a fingerprint for identification.
5
How can astronomers determine which elements are present in a star?
Model answer
By analysing the spectral lines, since each element produces a unique pattern of lines that can be used for identification.
6
What is a continuous spectrum and what type of object produces it?
Model answer
A continuous spectrum contains all wavelengths of light with no gaps, produced by hot dense objects like the interior of stars.

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