Question

Diffraction can be used to provide a quick test of the size of red blood cells. Blood is smeared onto a slide, and a laser shines through the slide. The size of the cells is very consistent, so the multiple diffraction patterns overlap and produce an overall pattern that is similar to what a single cell would produce. Ideally, the diameter of a red blood cell should be between 7.5 and 8.0 μm.

If a 633 nm laser shines through a slide and produces a pattern on a screen 24.0 cm distant, what range of sizes of the central maximum should be expected?

Answer 1

Using diffraction, the size of the central maximum produced by a 633 nm laser passing through red blood cells can provide estimates of their size. The calculations involve substituting known dimensions into the single-slit diffraction formula, showing a practical application of physics in biological measurement.

Step-by-step explanation:

The student's question involves the principles of diffraction and how it can be applied to estimate the size of red blood cells. When illuminated with a 633 nm laser, the blood smear on a slide creates a diffraction pattern where the central maximum can provide hints about the cell size.

Considering the ideal diameter of a red blood cell is between 7.5 and 8.0 μm, the size of the central maximum on a screen placed at 24.0 cm from the slide can be calculated using the formula for diffraction through a single slit, which is λD/w, where λ is the laser wavelength, D is the distance to the screen, and w is the width of the slit (or cell).

For an ideal cell size of 7.5 to 8.0 μm, we'd expect the central maximum to be within a certain range on the screen. Calculating this requires us to solve for D/w using the provided measurements, and substituting realistic cell widths to find the expected size of the central maximum pattern on the screen. The exercise is a practical application of diffraction to biological measurements and employs our understanding of light microscopy and cell dimensions.

Answer 2

Using diffraction, the size of the central maximum produced by a 633 nm laser passing through red blood cells can provide estimates of their size. The calculations involve substituting known dimensions into the single-slit diffraction formula, showing a practical application of physics in biological measurement.

Step-by-step explanation:

The student's question involves the principles of diffraction and how it can be applied to estimate the size of red blood cells. When illuminated with a 633 nm laser, the blood smear on a slide creates a diffraction pattern where the central maximum can provide hints about the cell size.

Considering the ideal diameter of a red blood cell is between 7.5 and 8.0 μm, the size of the central maximum on a screen placed at 24.0 cm from the slide can be calculated using the formula for diffraction through a single slit, which is λD/w, where λ is the laser wavelength, D is the distance to the screen, and w is the width of the slit (or cell).

For an ideal cell size of 7.5 to 8.0 μm, we'd expect the central maximum to be within a certain range on the screen. Calculating this requires us to solve for D/w using the provided measurements, and substituting realistic cell widths to find the expected size of the central maximum pattern on the screen. The exercise is a practical application of diffraction to biological measurements and employs our understanding of light microscopy and cell dimensions.