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Bloop
The three isotopes 212Po, 137Cs, and 90Sr decay as 212Po→208Pb+α, 137Cs→137Ba+e−+γ, and 90Sr→90Y+e−.?
Which of these isotopes would be most useful as a biological tracer?
Kenya4 weeks agoA standardized biological microscope has an 8.0-mm-focal-length objective.?
What focal-length eyepiece should be used to achieve a total magnification of 100×?
1 AnswerPhysics1 month agoA camera takes a properly exposed photo at f/5.6 and 1/500 s.?
What shutter speed should be used if the lens is changed to f/4.0?
Options:
1/125 s
1/250 s
1/500 s
1/1000 s
1/2000 s
Physics1 month agoTo focus parallel light rays to the smallest possible spot, should you use a lens with a small f-number or a large f-number?
A _____________f-number is required ___________.
Options:
small
large
------
since the spot size decreases with the increasing focal length
otherwise larger spherical aberration appears
otherwise larger chromatic aberration appears
since the spot size is proportional to the focal length and inversely proportional to the diameter
1 AnswerPhysics1 month agoThe center of the galaxy is filled with low-density hydrogen gas that scatters light rays. ?
An astronomer wants to take a picture of the center of the galaxy.Will the view be better using ultraviolet light, visible light, or infrared light? Explain.
The view will be better using _________light because it _____________.
Options:
UV
visible
infrared
-----
is scattered less than the other two
has smaller index of refraction
is absorbed less than the other 2
Physics1 month agoSuppose a camera's exposure is correct when the lens has a focal length of 8.0 mm.?
Will the picture be overexposed, underexposed, or still correct if the focal length is "zoomed" to 16.0 mm without changing the diameter of the lens aperture? Explain.
If the shutter speed remains the same, the picture will be ___________ because the intensity of light reaching the detector ____________.
Options:
overexposed
underexposed
correct
---------
increases with an increasing focal lenght
decreases with an increasing focal length
depends on the amount of light refracted by the first lens which remains the same
Physics1 month agoA keratometer is an optical device used to measure the radius of curvature of the eye’s cornea—its entrance surface. ?
This measurement is especially important when fitting contact lenses, which must match the cornea’s curvature.
Most light incident on the eye is transmitted into the eye, but some light reflects from the cornea, which, due to its curvature, acts like a convex mirror.
The keratometer places a small, illuminated ring of known diameter 7.5 cm in front of the eye. The optometrist, using an eyepiece, looks through the center of this ring and sees a small virtual image of the ring that appears to be behind the cornea. The optometrist uses a scale inside the eyepiece to measure the diameter of the image and calculate its magnification.
Suppose the optometrist finds that the magnification for one patient is 0.049.
What is the absolute value of the radius of curvature of her cornea?
Physics2 months agoA 3.8 cm -thick layer of oil is sandwiched between a 1.7 cm -thick sheet of glass and a 2.4 cm -thick sheet of polystyrene plastic.?
How long (in ns) does it take light incident perpendicular to the glass to pass through this 7.9 cm -thick sandwich?
1 AnswerPhysics2 months agoYou've been asked to build a telescope from a 2.0× magnifying lens and a 5.0× magnifying lens.?
Which lens should be used as the objective?
options:
2.0×
5.0×
What will be the length of your telescope?
Physics2 months agoA 3.8 cm -thick layer of oil is sandwiched between a 1.7 cm -thick sheet of glass and a 2.4 cm -thick sheet of polystyrene plastic.?
How long (in ns) does it take light incident perpendicular to the glass to pass through this 7.9 cm -thick sandwich?
Physics2 months ago
Points 1 and 2 in (Figure 1) are the same distance from the wires as the point where B = 1.7 mT.?
What is the strength and direction of B⃗ at point 1?
What is the strength and direction of B⃗ at point 2?
Physics2 months ago
Determine the magnetic field direction that causes the charged particle shown in the figure(Figure 1)?
Determine the magnetic field direction that causes the charged particle shown in the figure(Figure 1) (a) to experience the indicated magnetic force.
Determine the magnetic field direction that causes the charged particle shown in the figure (b) to experience the indicated magnetic force.
Physics2 months agoA camera takes a properly exposed photo at f/5.6 and 1/500 s.?
What shutter speed should be used if the lens is changed to f/4.0?
Options:
1/125 s
1/250 s
1/500 s
1/1000 s
1/2000 s
6 AnswersPhotography2 months agoEllen wears eyeglasses with the prescription -1.0 D?
What is her far point without the glasses?
2 AnswersOptical2 months agoA standardized biological microscope has an 8.0-mm-focal-length objective.?
What focal-length eyepiece should be used to achieve a total magnification of 100×?
2 AnswersPhysics2 months agoYou've been asked to build a telescope from a 2.0× magnifying lens and a 5.0× magnifying lens.?
Options:
10×
2.0×
2.5×
5.0×
2 AnswersAstronomy & Space2 months agoA 2.0-m-tall man is 10 m in front of a camera with a 21-mm-focal-length lens.?
How tall is his image on the detector?
Physics2 months agoA 2.1-cm-tall object is 28 cm to the left of a lens with a focal length of 14 cm . ?
A second lens with a focal length of 8.0 cm is 44 cm to the right of the first lens.
Calculate the distance between the final image and the second lens.
Calculate the image height.
Physics2 months agoTo focus parallel light rays to the smallest possible spot, should you use a lens with a small f-number or a large f-number?
A _____________f-number is required ___________.
Options:
small
large
------
since the spot size decreases with the increasing focal length
otherwise larger spherical aberration appears
otherwise larger chromatic aberration appears
since the spot size is proportional to the focal length and inversely proportional to the diameter
Optical2 months ago