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Question 19N.2.HL.TZ0.10c(ii)

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Date November 2019 Marks available [Maximum mark: 2] Reference code 19N.2.HL.TZ0.10c(ii)
Level HL Paper 2 Time zone TZ0
Command term Estimate Question number c(ii) Adapted from N/A
c(ii).
[Maximum mark: 2]
19N.2.HL.TZ0.10c(ii)

The lens of an optical system is coated with a thin film of magnesium fluoride of thickness d. Monochromatic light of wavelength 656 nm in air is incident on the lens. The angle of incidence is θ. Two reflected rays, X and Y, are shown.

The following refractive indices are available.

Air                            = 1.00
Magnesium fluoride = 1.38
Lens                         = 1.58

Light from a point source is incident on the pupil of the eye of an observer. The diameter of the pupil is 2.8 mm.

(c(ii))

Estimate, in rad, the smallest angular separation of two distinct point sources of light of wavelength 656 nm that can be resolved by the eye of this observer.

[2]

Markscheme

use of θ=1.22λb

θ=2.9×10-4 «rad» ✔

 

NOTE: Award [2] for bald correct answer