the distance between the centre of a lens and the focal point焦距 Examples from the Corpus focal length•Properties of a parabola All parabolas are similar.Focal lengtha determines the magnitude.•A singlefocal length, fixed-focus is often sufficient.•The image produced by a diverging lens...
From Longman Dictionary of Contemporary Englishˈfocal length noun [countable] technical the distance between the centre of a lens and the focal pointExamples from the Corpusfocal length• Properties of a parabola All parabolas are similar. Focal length a determines the magnitude.• A single fo...
If AB is a focal chord of x2−2x+y−2=0 whose focus is S and AS=l1, then find BS. View Solution If a focal chord of the parabola be at a distanced from the vertex, then its length is equal to View Solution If PQ is a focal chord of the parabola y2=4ax with focus at...
Properties of a parabola All parabolas are similar. Focal length a determines the magnitude. A discussion is made regarding scalingfocal length, optimization of stop distance and saving the time for OTF calculation. The relation between thefocal lengthof a concave lens and its reflective image prope...
In particular, the difference between these distances is always equal to the length of the major axis. The general equation for an "East-West opening hyperbola" is:x−h2a2−y−k2b2=1, while the general equation for a "North-South opening hyperbola" is:y−k2a2−x−h2b2&...
The length of a focal chord of the parabola y^(2) = 4ax at a distance... 03:32 What is the length of the focal distance from the point P(x(1),y(1))on... 02:24 the distance of a focal chord of the parabola y^(2)=16x from its verte... 03:14 If the area of the tria...
Testing the optical figure and focal length of laser mirrors with radii of curvature in the 10 to 100 m range is difficult. If the mirror is concave, a source can be placed at the center of curvature. Air turbulence over these long path lengths makes interferometry difficult, however, and ...
Note: Using this second definition, thesumof the focal radii of anellipseis aconstant. It is the same as the length of themajor diameter. Thedifferenceof the focal radii of ahyperbolais a constant. It is the distance between thevertices. ...
Panasonic introduces new single focal-length lens So, in order to focus the beam at a focal distance [d.sub.f], the variation of phase along the aperture, must be: Near-field focusing in one plane using a loaded sectoral horn antenna The laser head must first be taken to the start pos...
The property of an ellipse or hyperbola whereby lines drawn from the foci to any point on the conic make equal angles with the tangent to the conic at that point. The property of a parabola whereby a line from the focus to any point on the parabola, and a line through this point paral...