7 Light and Optics in Biology and Medicine Online Quiz Questions

When light crosses from one material into another, which statement about its frequency and wavelength is correct?

True or false: Rods are highly sensitive in dim light, while cones support color vision and fine detail.

A lab wants to view a stained tissue section using contrast formed by light transmitted through or absorbed by the specimen. Which microscopy method best fits this goal?

A fluorescent label absorbs light and then emits light. Which relationship between the absorbed and emitted light is typical?

Which spectroscopy method uses small wavelength shifts in light scattered by molecules to provide information about molecular vibrations and chemical composition?

Select all the microscopy methods described as able to reveal structures in transparent, living cells without staining by converting optical-path differences into image contrast.

For a uniform, dilute solution, use $A=\varepsilon c\ell$. If $\varepsilon=200\ \mathrm{L\,mol^{-1}\,cm^{-1}}$, $c=0.002\ \mathrm{mol\,L^{-1}}$, and $\ell=1\ \mathrm{cm}$, what is the absorbance $A$?

True or false: Pulse oximetry estimates arterial oxygen saturation noninvasively by comparing light absorption at selected wavelengths.

Select all statements that describe limitations or potential biological impacts of optical methods in tissue or living samples.

An eye focuses images of distant objects in front of the retina. Which refractive error does this describe?

A microscope image is made larger, but two nearby structures still appear as one. Explain why increased magnification alone may not make the structures distinguishable, and name two factors that influence resolution.

In dim light, which retinal photoreceptors are especially important for detecting visual information?

According to $E=hf$, what happens to a photon's energy if its frequency doubles?

A researcher wants to see structures in transparent, living cells without staining them. Which method is designed to create contrast from differences in optical path through the sample?

A fluorescent label absorbs higher-energy light. Which description best characterizes the light it typically emits?

The crystalline lens changes shape to adjust the eye's focus for objects at different distances.

Which spectroscopy method measures small wavelength shifts in light scattered by molecules to provide information about molecular vibrations?

A uniform, dilute solution has molar absorptivity $\varepsilon=120\ \mathrm{L\,mol^{-1}\,cm^{-1}}$, concentration $c=0.002\ \mathrm{mol\,L^{-1}}$, and optical path length $\ell=1\ \mathrm{cm}$. Using $A=\varepsilon c\ell$, calculate its absorbance. Enter a decimal number.