Chemistry, 11.07.2019 20:40, ashleydenson1517

What are the similarities and differences between a camera and a camera and the human eye?

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The “screen” in a camera is flat, whereas the retina is curved.
Both eye and camera have limited fields of vision.
Both eye and camera use a transparent convex lens to form an image.
The sensitivity of the eye and the acuity are not constant over the retina, acuity and sensitivity being governed by the distribution of rods and cones on the retina; whereas the sensitivity of the camera film or electronic photosensitive light receptors is distributed evenly.
In a camera only air separates the screen from the lens; the eye is filled with liquid between the lens and the retina and this liquid adds to the refraction of the light.
Blood vessels come in front of the retina and therefore obscure the image, so the eye is in a state of minute motions to compensate for missing parts of the image; in a camera the screen is exposed only for a fraction of second usually to admit the required amount of light to form an image.
In the eye and the camera the lens produces an inverted image.
The eye produces an imperfect image containing chromatic aberration. The lens of a good camera produces minimal chromatic aberration.
The eye is only the start of the vision process and the brain has to learn to translate the image to make it meaningful. The process in the camera is mainly the result of optics directly.
The eye produces a chemical (visual purple) which improves and accommodates vision for different light levels. A camera is more limited for such accommodation. This is noticeable in pictures taken in artificial or low light.
As light level decreases, both eye and camera tend towards monochromatic images.
A camera can be made sensitive to frequencies of light outside the visual range, including ultraviolet and infrared. The eye is limited to a smaller range of light frequencies.
The camera can be used for lengthy exposures while the eye has to operate at a speed dictated by nerve impulses.

answered: Guest

part 1: the half-life of the element is 22 years.

part 2: it will take 132.02 year for the sample to decay from 308.0 g to 4.8125 g.

explanation:

part 1: there are two ways to determine the half life time.

first way: the half life time can be determined directly from its definition as it is the time required for the sample to decay to its half concentration.

from the data the initial concentration was 45.0 g and decayed to its half value (22.5 g) in 22.0 years.

second way: the radio active decay is considered first order reaction so we can use the laws of first order reactions.

k = (1/t) ln (a/a-x), where k is the rate constant of the reaction,

t is the time of the reaction

a is the initial concentration of the reactant

a-x is the remaining concentration at time (t)

a = 45.0 g the initial concentration at t = 0 year.

at t = 22 year, a-x = 22.5 g

then k = (1/22 year) ln (45.0 g/ 22.5 g) = 0.0315 year-1.

the half-life time (t1/2) = ln 2/ k = 0.693/ k =0.693/ 0.0315 = 22 years.

part 2:

using the same law k = (1/t) ln (a/a-x),