MCAT Physical : Light
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Example Questions
Example Question #1 : Electromagnetic Spectrum
Which color of the visible spectrum of light has the highest energy of the answer choices?
Red
Orange
Green
Blue
Yellow
Blue
The highest energy of any visible light belongs to violet. The greater the wavelength, the lower the energy of the light. The greater the frequency, the higher the energy of the light. This is why ultraviolet light ("ultra" meaning "beyond" violet) is so damaging to DNA. Out of the answer choices, blue light has the lowest wavelength and greatest frequency, making it the highest energy.
Example Question #31 : Ap Physics 2
Which of the following waves carry the greatest amount of energy?
X-rays
Gamma rays
Radio waves
Infrared waves
Ultraviolet light
Gamma rays
The energy of a wave increases with increasing frequency and decreasing wavelength. Considering these different waves, radiowaves possess the longest wavelengths and gamma rays the shortest wavelength, thus gamma rays carry the greatest amount of energy.
Example Question #181 : Ap Physics 2
Which of the following is/are ionizing radiation?
- microwaves
- X-rays
- gamma rays
- all of the above
- 2 and 3, but not 1
2
1
3
5
4
5
Choice 5 is correct. Highly energetic frequencies such as X-rays and gamma rays can displace electrons from materials upon which they impinge. Microwaves are a form of radio waves, which are long-wavelength, low frequency waves with little energy.
Mnemonic: Microwave ovens are fundamentally safe household items.
Example Question #24 : Light
An incandescent light bulb is shown through a glass prism. The certain wavlength of the light is then directed into a glass cuvette containing an unknown concentration of protein. Commonly, this process is called spectroscopy and is used to determine the concentrations of DNA, RNA, and proteins in solutions. The indices of reflection of air, glass, and the solution are 1, 1.5, and 1.3, respectively.
Light is a __________.
particle
wave
particle and a wave
particle or wave, depending on wavelength
particle and a wave
As Einstein determined, light has properties of both a particle and a wave. In the particle sense, it has mass, velocity, and momentum. The wave property of light allows for diffraction, and constructive and destructive interference. For the MCAT, it is important to know that the photon (the particle of light) has both particle and wave properties. In fact, all objects have both particle and wave properties; however, their wave property becomes less obvious with increasing mass.
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