Chapter 5 home work 10 Light and Matter Flashcards
Suppose you watch a leaf bobbing up and down as ripples pass it by in a pond. You notice that it does two full up and down bobs each second. Which statement is true of the ripples on the pond?
They have a wavelength of two cycles per second. We can calculate the wavelength of the ripples from their frequency. They have a frequency of 2 hertz. They have a frequency of 4 hertz.
They have a frequency of 2 hertz.
Suppose you know the frequency of a photon and the speed of light. What else can you determine about the photon?
its wavelength and energy the chemical composition of the object that emitted it its temperature its acceleration
its wavelength and energy
When considering light as made up of individual “pieces,” each characterized by a particular amount of energy, the pieces are called _________.
frequencies wavicles gamma rays photons
photons
From shortest to longest wavelength, which of the following correctly orders the different categories of electromagnetic radiation?
gamma rays, X rays, ultraviolet, visible light, infrared, radio infrared, visible light, ultraviolet, X rays, gamma rays, radio gamma rays, X rays, visible light, ultraviolet, infrared, radio radio, infrared, visible light, ultraviolet, X rays, gamma rays
gamma rays, X rays, ultraviolet, visible light, infrared, radio
Which forms of light are lower in energy and frequency than the light that our eyes can see?
visible light ultraviolet and X rays infrared and ultraviolet infrared and radio
infrared and radio
If we say that a material is opaque to ultraviolet light, we mean that it _________.
transmits ultraviolet light Reflects ultraviolet light absorbs ultraviolet light emits ultraviolet light
absorbs ultraviolet light
Which of the following transitions within an atom is not possible?
An electron begins in the ground state and then gains enough energy to jump to an excited state. An electron begins in an excited state and then gains enough energy to jump to the ground state. An electron begins in an excited state and then gains enough energy to become ionized. An electron begins in the ground state and then gains enough energy to become ionized.
An electron begins in an excited state and then gains enough energy to jump to the ground state.
Thermal radiation is defined as _________.
radiation that is felt as heat radiation with a spectrum whose shape depends only on the temperature of the emitting object radiation produced by an extremely hot object radiation in the form of emission lines from an object
radiation with a spectrum whose shape depends only on the temperature of the emitting object
According to the laws of thermal radiation, hotter objects emit photons with _________.
a lower average frequency a shorter average wavelength a higher average speed a lower average energy
a shorter average wavelength
Suppose you want to know the chemical composition of a distant star. Which piece of information is most useful to you?
the Doppler shift of the star's spectrum the peak energy of the star's thermal radiation the wavelengths of spectral lines in the star's spectrum whether the star's spectrum has more emission lines or more absorption lines
the wavelengths of spectral lines in the star’s spectrum
Study the graph of the intensity of light versus wavelength for continuous spectra, observing how it changes with the temperature of the light bulb. Recall that one of the laws of thermal radiation states that a higher-temperature object emits photons with higher average energy (Wien’s law). This law is illustrated by the fact that for a higher temperature object, the graph peaks at __________.
a higher intensity a shorter wavelength a longer wavelength
a shorter wavelength
Click “show” for the emission line spectrum, then click “choose gases” and study the emission line spectrum for neon. The neon “OPEN” sign appears reddish-orange because __________.
neon atoms emit many more yellow and red photons than blue and violet photons the yellow and red photons emitted by neon travel much faster than the blue and violet photons and so reach our eyes first neon atoms emit only yellow and red photons each yellow and red photon emitted by neon carries more energy than each blue and violet photon emitted.
neon atoms emit many more yellow and red photons than blue and violet photons
The absorption line spectrum shows what we see when we look at a hot light source (such as a star or light bulb) directly behind a cooler cloud of gas. Suppose instead that we are looking at the gas cloud but the light source is off to the side instead of directly behind it. In that case, the spectrum would __________.
appear as a continuous rainbow of colors be an emission spectrum appear completely dark still be an absorption spectrum
be an emission spectrum
What type of visible light spectrum does the Sun produce?
a continuous spectrum an emission line spectrum an absorption line spectrum
an absorption line spectrum
Which of the following statements is true of green grass?
It transmits all colors of light except green. It absorbs red light and reflects green light. It absorbs red light and emits green light.
It absorbs red light and reflects green light.
