What does the Rayleigh Criterion describe?

A. The maximum intensity of light in a diffraction pattern

B. The speed of light in different mediums

C. The minimum separation between two point sources that can be resolved

D. The angle of incidence in a prism

Which factor does NOT directly affect the resolution of an optical instrument?

A. Wavelength of light used

B. Aperture size of the instrument

C. Distance between the object and the instrument

D. Refractive index of the medium

What is the primary limitation that prevents optical microscopes from resolving atomic structures?

A. Mechanical vibrations

B. Diffraction of light

C. Refraction of light

D. Absorption of light

In terms of resolution, what happens when the aperture size of an optical instrument is increased?

A. Resolution decreases

B. Resolution increases

C. Resolution remains the same

D. Resolution becomes infinite

According to the Rayleigh Criterion, two point sources are just resolvable when:

A. The central maximum of one coincides with the first minimum of the other

B. The central maximum of one coincides with the central maximum of the other

C. The first minimum of one coincides with the first minimum of the other

D. The two point sources are at least one wavelength apart

a) Explain the Rayleigh Criterion and its significance in determining the resolution of optical instruments. [3]

b) A telescope has an objective lens diameter of 2.5 m. If it is used to observe a star emitting light of wavelength 550 nm, calculate the minimum angular separation between two stars that the telescope can resolve. [4]

a) Describe the phenomenon of diffraction limit in the context of optical resolution. [3]

b) If an optical microscope has a numerical aperture of 1.25 and is used with light of wavelength 450 nm, determine its resolution limit. [3]

a) Explain how thin films can lead to both constructive and destructive interference of light. [3]

b) A soap bubble appears green (wavelength = 530 nm) when illuminated with white light. If the refractive index of the soap is 1.33, calculate the minimum thickness of the bubble that results in this observed colour. [4]

a) Explain the significance of the Rayleigh Criterion in determining the resolution of optical systems. [3]

b) A double slit experiment is set up with a slit separation of 0.5 mm and is illuminated with light of wavelength 600 nm. Calculate the angular width of the central maximum on a screen placed 2 m away. [3]

c) How would the angular width change if the wavelength of the light used is increased? [2]

a) Describe the phenomenon of thin film interference. [3]

b) A film of oil on water appears to have a blue hue when illuminated with white light. If the blue light has a wavelength of 470 nm and the refractive index of the oil is 1.45, determine the minimum thickness of the oil film. [4]

c) How would the observed colour change if the thickness of the oil film is increased? [2]

Why is blue light better than red light for improving the resolution of an optical instrument?

A. Blue light has a longer wavelength

B. Blue light has a shorter wavelength

C. Blue light has a higher intensity

D. Blue light has a lower frequency

Which of the following is NOT a method to improve the resolution of optical instruments beyond the diffraction limit?

A. Using shorter wavelength light

B. Increasing the distance between the object and the instrument

C. Using a larger aperture

D. Using computational methods to reconstruct the image

What is the primary reason for the diffraction limit in optical instruments?

A. Imperfections in the lens

B. Absorption of light by the medium

C. Spreading out of light waves as they pass through an aperture

D. Reflection of light at the boundaries

In the context of resolution, what does "overcoming the diffraction limit" mean?

A. Increasing the intensity of light

B. Resolving details that are smaller than the wavelength of light used

C. Using multiple lenses in an optical instrument

D. Increasing the aperture size of the instrument

For a given optical instrument, if the wavelength of light used is halved, how does this affect the diffraction limit?

A. The diffraction limit is halved

B. The diffraction limit is doubled

C. The diffraction limit remains the same

D. The diffraction limit is quadrupled

a) What is the diffraction limit and how does it affect the resolution of optical instruments? [3]

b) An optical microscope has a numerical aperture of 1.3. Calculate its resolution limit when used with light of wavelength 520 nm. [3]

c) Suggest a method to improve the resolution of the microscope beyond the diffraction limit. [2]

a) Describe the principle behind Young's double-slit experiment. [3]

b) In a double-slit experiment, the slit separation is 0.4 mm and the distance to the screen is 1.5 m. If the fringe spacing observed is 1 cm, determine the wavelength of the light used. [4]

c) How would the fringe spacing change if the distance to the screen is increased? [2]

a) Explain the Rayleigh Criterion and its importance in determining the resolution of optical systems. [3]

b) A telescope has an objective lens diameter of 2.5 m. Calculate the resolution limit of this telescope when observing a star using light of wavelength 550 nm. [3]

c) If the telescope is used to observe two stars that are very close to each other, what would be the minimum angular separation between them for the telescope to resolve them as two distinct stars? [3]

d) How would the resolution limit change if the diameter of the objective lens is increased? [2]

a) Describe the phenomenon of thin film interference and how it leads to the appearance of colours on a film. [3]

b) A soap bubble appears green when illuminated with white light. If the green light has a wavelength of 510 nm and the refractive index of the soap bubble is 1.33, determine the minimum thickness of the soap bubble. [4]

c) Explain why increasing the thickness of the soap bubble might lead to a change in the observed colour. [3]

d) How would the observed colour of the soap bubble change if it is viewed under a light of a shorter wavelength? [2]

a) What is the significance of the diffraction limit in optical microscopy? [3]

b) An optical microscope has a numerical aperture of 1.4. Calculate its resolution limit when used with light of wavelength 480 nm. [3]

c) Suggest a method to improve the resolution of the microscope beyond the diffraction limit. [3]

d) How would the resolution of the microscope be affected if it is used in a medium with a higher refractive index? [3]