Question

A fluorescence microscope with an objective lens of numerical aperture (NA) 1.5 is used with light of wavelength ((lambda)) 600 nanometers. The lateral resolution limit of this microscope rounded off to the nearest integer, is ____ nanometers.

Hint:

When using fluorescence microscopy, choosing a higher numerical aperture can significantly improve resolution, allowing finer details to be resolved.

Answer 1

The resolution limit of a microscope can be estimated using the Rayleigh criterion for lateral resolution: \[ d = \frac{0.61 \lambda}{NA} \]

where:

• \( d \) is the lateral resolution limit,
• \( \lambda \) is the wavelength of light used,
• \( NA \) is the numerical aperture of the objective lens.

Step 1: Substituting the given values. \[ d = \frac{0.61 \times 600 \, \text{nm}}{1.5} \] Step 2: Calculating the resolution limit. \[ d = \frac{366 \, \text{nm}}{1.5} \approx 244 \, \text{nm} \] Conclusion:

Explanation: The formula used here is a simplified version of the Rayleigh criterion, which is suitable for calculating the diffraction-limited resolution in microscopy. This criterion is essential for determining the finest detail visible under a microscope given a particular light wavelength and numerical aperture.