Test on Resolving power of a microscope
Resolving Power of a Microscope: Understanding Resolution Limits
Test: Mikroskopie
20 questions
Question 1: Increasing the refractive index of the medium between the objective lens and the specimen decreases the resolving power of a microscope.
A. Yes
B. No
Explanation: To achieve higher resolution (a smaller resolution limit 'd'), the numerical aperture (NA) of the objective lens must be increased. The numerical aperture is defined as NA = n · sin α, where 'n' is the refractive index of the medium between the objective lens and the specimen. Therefore, increasing the refractive index 'n' directly increases the numerical aperture, which in turn leads to an increase in resolving power, not a decrease.
Question 2: The de Broglie wavelength of electrons accelerated by a voltage of 100 kilovolts is approximately 150,000 times shorter than the wavelength of green light.
A. Yes
B. No
Explanation: The study materials state: 'For example, electrons accelerated by a voltage of 100 kilovolts (kV) have a wavelength of approximately 0.0037 nm. This is about 150,000 times shorter than the wavelength of green light.'
Question 3: A light microscope with high magnification is always capable of distinguishing between two extremely close objects with greater clarity, regardless of its resolution.
A. Yes
B. No
Explanation: Resolution, or resolving power, is the ability of an optical instrument to distinguish two adjacent points or objects as separate. High magnification without sufficient resolution is referred to as 'empty magnification' because it simply makes a blurry image larger without revealing any new detail. Therefore, high magnification alone does not guarantee greater clarity in distinguishing extremely close objects; high resolution is essential for this capability.
Question 4: A Scanning Electron Microscope (SEM) can typically achieve a resolution of 0.05 nm.
A. Yes
B. No
Explanation: SEMs typically have a resolution range of about 0.5 nm to 20 nm. The resolution of 0.05 nm is characteristic of a Transmission Electron Microscope (TEM), which offers the highest resolution.
Question 5: Is 'empty magnification' a term used when high magnification results in a larger image but no new detail is revealed due to insufficient resolution?
A. Yes
B. No
Explanation: High magnification without sufficient resolution is referred to as 'empty magnification' because it simply makes a blurry image larger without revealing any new detail. This concept highlights that resolution, not just magnification, is key to observing fine structures clearly.