Q38.1
In an experiment to demonstrate the photoelectric effect, you shine a beam of monochromatic blue light on a metal plate.
As a result, electrons are emitted by the plate.
If you increase the intensity of the light but keep the color of the light the same, what happens?
1. More electrons are emitted per second
2. The maximum kinetic energy of the emitted electrons increases
3. Both 1. and 2.
4. Neither 1. nor 2.

A38.1
In an experiment to demonstrate the photoelectric effect, you shine a beam of monochromatic blue light on a metal plate.
As a result, electrons are emitted by the plate.
If you increase the intensity of the light but keep the color of the light the same, what happens?
1. More electrons are emitted per second
2. The maximum kinetic energy of the emitted electrons increases
3. Both 1. and 2.
4. Neither 1. nor 2.

Q38.2
A certain atom has two energy levels whose energies differ by
2.5 eV.
In order for a photon to excite an electron from the lower energy level to the upper energy level, what must be true about the energy of the photon?
1. its energy must be greater than or equal to 2.5 eV
2. its energy must be exactly 2.5 eV
3. its energy must be less than or equal to 2.5 eV
4. none of the above

A38.2
A certain atom has two energy levels whose energies differ by
2.5 eV.
In order for a photon to excite an electron from the lower energy level to the upper energy level, what must be true about the energy of the photon?
1. its energy must be greater than or equal to 2.5 eV
2. its energy must be exactly 2.5 eV
3. its energy must be less than or equal to 2.5 eV
4. none of the above

Q38.3
A certain atom has only three energy levels. From lowest to highest energy, these levels are denoted n = 1, n = 2, and n = 3.
When the atom transitions from the n = 3 level to the n = 2 level, it emits a photon of wavelength 800 nm. When the atom transitions from the n = 2 level to the n = 1 level, it emits a photon of wavelength 200 nm.
What is the wavelength of the photon emitted when the atom transitions from the n = 3 level to the n = 1 level?
1. 1000 nm
2. 600 nm
3. 500 nm
4. 160 nm

A38.3
A certain atom has only three energy levels. From lowest to highest energy, these levels are denoted n = 1, n = 2, and n = 3.
When the atom transitions from the n = 3 level to the n = 2 level, it emits a photon of wavelength 800 nm. When the atom transitions from the n = 2 level to the n = 1 level, it emits a photon of wavelength 200 nm.
What is the wavelength of the photon emitted when the atom transitions from the n = 3 level to the n = 1 level?
1. 1000 nm
2. 600 nm
3. 500 nm
4. 160 nm

Q38.4
In the Bohr model of the hydrogen atom, an electron in the n = 2 orbit has
1. a higher total energy and a higher kinetic energy than an electron in the n =1 orbit
2. a lower total energy and a higher kinetic energy than an electron in the n =1 orbit
3. a higher total energy and a lower kinetic energy than an electron in the n =1 orbit
4. a lower total energy and a lower kinetic energy than an electron in the n =1 orbit
5. none of the above

A38.4
In the Bohr model of the hydrogen atom, an electron in the n = 2 orbit has
1. a higher total energy and a higher kinetic energy than an electron in the n =1 orbit
2. a lower total energy and a higher kinetic energy than an electron in the n =1 orbit
3. a higher total energy and a lower kinetic energy than an electron in the n =1 orbit
4. a lower total energy and a lower kinetic energy than an electron in the n =1 orbit
5. none of the above

Q38.5
When an x-ray photon bounces off an electron,
1. the photon wavelength decreases and the photon frequency decreases
2. the photon wavelength decreases and the photon frequency increases
3. the photon wavelength increases and the photon frequency decreases
4. the photon wavelength increases and the photon frequency increases
5. none of the above

A38.5
When an x-ray photon bounces off an electron,
1. the photon wavelength decreases and the photon frequency decreases
2. the photon wavelength decreases and the photon frequency increases
3. the photon wavelength increases and the photon frequency decreases
4. the photon wavelength increases and the photon frequency increases
5. none of the above

Q38.6
If you increase the temperature of a blackbody,
1. it emits more radiation at very short wavelengths and more radiation at very long wavelengths
2. it emits more radiation at very short wavelengths but less radiation at very long wavelengths
3. it emits less radiation at very short wavelengths but more radiation at very long wavelengths
4. it emits less radiation at very short wavelengths and less radiation at very long wavelengths
5. none of the above

A38.6
If you increase the temperature of a blackbody,
1. it emits more radiation at very short wavelengths and more radiation at very long wavelengths
2. it emits more radiation at very short wavelengths but less radiation at very long wavelengths
3. it emits less radiation at very short wavelengths but more radiation at very long wavelengths
4. it emits less radiation at very short wavelengths and less radiation at very long wavelengths
5. none of the above