Light of wavelength is used in air to examine a specimen

PHYSICS · Single correct · A Level · Physics · Waves · Waves

Problem

Light of wavelength

600\,\text{nm}

is used in air

(n=1)

to examine a specimen. To resolve details

0.50\;\mu\text{m}

apart, the microscope objective must have a semi-aperture angle

\alpha

such that

\text{NA}=\sin\alpha

. The required value of

\alpha

is closest to (a)

37^{\circ}

(b)

42^{\circ}

(c)

53^{\circ}

(d)

30^{\circ}