If more than one wavelength is present ( as is usually the case ), one must sum or integrate over the spectrum of wavelengths present to get the total luminous intensity.

If measured instead per unit wavelength, using Wien's law, the peak is at 1. 06 mm corresponding to a frequency of 283 GHz.

If the width of the slits is small enough ( less than the wavelength of the laser light ), the slits diffract the light into cylindrical waves.

If the width of the slits is greater than the wavelength, the Fraunhofer diffraction equation gives the intensity of the diffracted light as:

If applied to optical wavelengths, this manifests itself as a change in the colour of visible light as the wavelength of the light is increased toward the red part of the light spectrum.

If the beam of light is not orthogonal ( or rather normal ) to the boundary, the change in wavelength results in a change in the direction of the beam.

If the pitch of this twist is on the order of the wavelength of visible light, then interesting optical interference effects can be observed.

If two waves of the same wavelength and frequency are in phase, both the wave crests and wave troughs align.

If the wavelength is much shorter than the target's size, the wave will bounce off in a way similar to the way light is reflected by a mirror.

If the wavelength is much longer than the size of the target, the target may not be visible because of poor reflection.

If λ represents wavelength and f represents frequency ( note, λf = c where c is the speed of light ), then z is defined by the equations:

If the waves have the correct frequency ( or wavelength ) and polarization, their energy can be transferred to the charged particles in the plasma, which in turn collide with other plasma particles, thus increasing the temperature of the bulk plasma.

If each mode received an equal partition of energy, the short wavelength modes would consume all the energy.

If scatterers are arranged symmetrically with a separation d, these spherical waves will be in sync ( add constructively ) only in directions where their path-length difference 2d sin θ equals an integer multiple of the wavelength λ.

If λ < sub > c </ sub > is the central wavelength, λ < sub > 0 </ sub > is the central wavelength at normal incidence, and n < sup >*</ sup > is the filter effective index of refraction, then:

If the surface is rough enough to create path-length differences exceeding one wavelength, giving rise to phase changes greater than 2π, the amplitude, and hence the intensity, of the resultant light varies randomly.

If a photographic plate or another 2-D optical sensor is located within the scattered light field without a lens, a speckle pattern is obtained whose characteristics depend on the geometry of the system and the wavelength of the laser.

If a particle were massive enough that its Compton wavelength and Schwarzschild radius were approximately equal, its dynamics would be strongly affected by quantum gravity.

If the source has a maximum overall dimension or aperture width ( D ) that is large compared to the wavelength λ, the far-field region is commonly taken to exist at distances from the source, greater than Fresnel parameter S = D < sup > 2 </ sup >/( 4λ ), S > 1.

If photons of a particular wavelength are absorbed by matter, then when we observe light reflected from or transmitted through that matter, what we see is the complementary color, made up of the other visible wavelengths remaining.

If only a single atom of hydrogen were present, then only a single wavelength would be observed at a given instant.

If light of a fixed frequency / wavelength / color ( as from a laser ) is assumed, then the time-harmonic ( frequency-domain ) form of the optical field is given as:

If the wavelength of a quantum particle is short enough, atoms or their nuclei can serve as diffraction obstacles.

If she did, he could stand it better in the light.

If the input light distribution falls beyond the visible range, Af as expected, since Af.

If it pleases symphony audiences as a light, jolly piece, a series of impressions musically expressed, it succeeds.

If light moves instantaneously, the telescope does not move, and the true direction of the star relative to the observer can be found by following the line ES.

If, in an unsharp image, a patch of light corresponds to an object point, the center of gravity of the patch may be regarded as the image point, this being the point where the plane receiving the image, e. g., a focusing screen, intersects the ray passing through the middle of the stop.

If appropriate proportions of three primary pigments are mixed, the result reflects so little light as to be called " black ".

If the source emits light uniformly in all directions, the flux can be found by multiplying the intensity by 4π: a uniform 1 candela source emits 12. 6 lumens.

If it is removed, the light ceases.

If the glass is cooled quickly in the absence of a strong light source by putting ice on the glass or placing it in the freezer with the door almost closed, it turns backwards ( i. e. the silver sides trail ).

If light pressure were the cause of the rotation, then the better the vacuum in the bulb, the less air resistance to movement, and the faster the vanes should spin.

If the incident light is monochromatic, these sources all have the same phase.

If light consisted strictly of ordinary or classical particles, and these particles were fired in a straight line through a slit and allowed to strike a screen on the other side, we would expect to see a pattern corresponding to the size and shape of the slit.

If a ray tracing is then made as if a light wave ( as understood in classical physics ) is wide enough to take both paths, then that ray tracing will accurately predict the appearance of maxima and minima on the detector screen when many particles pass through the apparatus and gradually " paint " the expected interference pattern.

If the emulsion is dilute enough, higher-frequency and low-wavelength light will be scattered more, and the emulsion will appear bluer-this is called the " Tyndall effect ".

If the incident light is unpolarised ( containing an equal mix of s-and p-polarisations ), the reflection coefficient is

If a laser is swept across a distant object, the spot of laser light can easily be made to move across the object at a speed greater than c. Similarly, a shadow projected onto a distant object can be made to move across the object faster than c. In neither case does the light travel from the source to the object faster than c, nor does any information travel faster than light.

If Lorentz symmetry can cease to be a fundamental symmetry at Planck scale or at some other fundamental scale, it is conceivable that particles with a critical speed different from the speed of light be the ultimate constituents of matter.

If his circumspection in regard to Philip's sensibilities went so far that he even refused to grant a dispensation for the marriage of Amadee's daughter, Agnes, to the son of the dauphin of Vienne -- a truly peacemaking move according to thirteenth-century ideas, for Savoy and Dauphine were as usual fighting on opposite sides -- for fear that he might seem to be favoring the anti-French coalition, he would certainly never take the far more drastic step of ordering the return of Gascony to Edward, even though, as he admitted to the English ambassadors, he had been advised that the original cession was invalid.

If the new Soviet series has followed the general pattern of previous Russian tests, the shots were roughly half fission and half fusion, meaning a fission yield of 30 to 40 megatons thus far.

If a branch extended out too far, each man held it back for the next, and if they met a low overhang, each warned the other.

If the latter knows nothing about the absent sitter except his name ( given by the experimenter ), he cannot possibly give any clues, conscious or unconscious, far less ask leading questions.

If the anchor continues to drag, or sets after having dragged too far, it should be retrieved and moved back to the desired position ( or another location chosen.

If we look at this situation from far above, so that we cannot see the supporters, we see the large balloon as a small object animated by erratic movement.

Mather began to publicize and celebrate the trials well before they were put to an end: " If in the midst of the many Dissatisfaction among us, the publication of these Trials may promote such a pious Thankfulness unto God, for Justice being so far executed among us, I shall Re-joyce that God is Glorified ..." ( Wonders of the Invisible World ).

If van der Heul was indeed of African ancestry, this fact would make him the highest ranking black pirate so far identified.

If two molecules react, not only molecules of the final reaction products are formed, but also some unstable molecules, having the property of being able to further react with the parent molecules with a far larger probability than the initial reactants.

If the viewing distance is large compared with the separation of the slits ( the far field ), the phase difference can be found using the geometry shown in the figure below right.

The parallel postulate: If two lines intersect a third in such a way that the sum of the inner angles on one side is less than two right angles, then the two lines inevitably must intersect each other on that side if extended far enough.

In 1563, Elizabeth told an imperial envoy: " If I follow the inclination of my nature, it is this: beggar-woman and single, far rather than queen and married ".

If the cities were treated as relatively autonomous local administrative areas, it would simplify the problems of imperial administration, which as far as Julian was concerned, should be focused on the administration of the law and defense of the empire's vast frontiers.

If this continues far enough, the working end passes into the knot and the knot unravels and fails.

If electrons ' move ' about the electron cloud in strict paths the same way planets orbit the sun, then electrons would be required to do so at speeds which far exceed the speed of light.

If your hip opens up, you have gone too far.

If the distribution of income within a country is skewed, a small wealthy class can increase per capita income far above that of the majority of the population.

You now have an open nose "; If the skill was too low, the player would insert the lock pick too far, killing himself.

If the objects are indeterminate until one of them is measured, then the question becomes, " How can one account for something that was at one point indefinite with regard to its spin ( or whatever is in this case the subject of investigation ) suddenly becoming definite in that regard even though no physical interaction with the second object occurred, and, if the two objects are sufficiently far separated, could not even have had the time needed for such an interaction to proceed from the first to the second object?

If the two devices are far enough apart or on separate power systems, the local ground connections at either end of the cable will have differing voltages ; this difference will reduce the noise margin of the signals.

If the frequencies were too far apart the heterodyne became ultrasonic and hence no longer audible.

If we imagine looking at the Earth from space, we see that the whole Earth was pulled, but the near oceans more and the far oceans less ; the far oceans stayed behind since they are pulled less ( since they are farther away ).

If a word has two vowels, one far back in the mouth and the other far forward, more effort is required to pronounce the word than if the vowels were closer, and therefore one possible linguistic development is for these two vowels to be drawn closer together.