Question

You switch from a 1.40NA60× oil immersion objective to a 1.40NA60× oil immersion objective. What are the acceptance angles for each? Compare and comment on the values. Which would you use first to locate the target area on your specimen?

a) 0.024 rad; 0.024 rad
b) 0.020 rad; 0.024 rad
c) 0.024 rad; 0.020 rad
d) 0.020 rad; 0.020 rad

Answer 1

The acceptance angles for both objective lenses are 0.024 rad. The order in which the lenses should be used does not depend on their acceptance angles.

Step-by-step explanation:

The acceptance angle, denoted by α, of an objective lens is given by the formula:

α = sin-1(nNA)

Where α is the acceptance angle, n is the refractive index of the medium between the lens and the specimen, and NA is the numerical aperture of the objective lens. In this case, both objective lenses have the same specifications, with a numerical aperture (NA) of 1.40 and a refractive index (n) of 1.

Therefore, the acceptance angles for both lenses would be the same: 0.024 rad.

Since both lenses have the same acceptance angle, it doesn't matter which one is used first to locate the target area on the specimen. The values of the acceptance angles do not determine the order in which the lenses should be used.