What Is Light And Energy Practical

Light waves are a form of electromagnetic waves, which consist of patterns of electric and magnetic energy. The visible spectrum is only a small part of the electromagnetic spectrum-the

Electromagnetic Radiation – A form of energy composed of waves of electric and magnetic changes (from electrically charged particles). It deals with

The illuminating parts of a microscope enable us to see the detail of the subject placed under the microscope. The three main parts that enable us to do this are: the condenser which illuminates the object that is placed under the microscope, the objectives which forms the magnified image, and the eyepiece which enables us to see the magnified

FIGURE 1.7- A magnified view of a single lenslet shows a portion of an aberrated wavefront (red curve) passing through. If the wavefront had been flat (aberration-free), it would have focused to a point on the video sensor (CCD) on the lenslet's optic axis (yellow dot). Refractive errors distort the wavefront out of a plane, so a wavefront portion (red curve) enters the lenslet curved and tilted. The light will therefore be focused to another part (red dot). The dot will be shifted by an amount that is in direct proportion to the wavefront tilt.

When a man stands near the edge of an empty drainage ditch of depth 2.80 m, he can barely see the boundary between the opposite wall and bottom of the ditch as shown. The distance from his eyes to the ground is 1.85 m. (a) What is the horizontal distance d from the man to the edge of the drainage ditch? (b) After the drainage ditch is filled with water as shown, what is the maximum distance x the man can stand from the edge and still see the same boundary? [Ans: 1.65 cm]

The thickness of glass that covers the specimen slide also affects the ability one has to focus the image. If the glass is too thick for the objective lens then one will have a difficult time getting a focused view (Alonzo p55).

It was then during the 1950’s that Zacharias Jansen and his father, Han Jansen, created the first high-powered compound light microscope. Images could be magnified up to 9x which was a novel feat at that time. Zacharias and his father created the device after experimenting with glasses and discovered that by placing multiple lens in a tube they could increase magnification. Unfortunately, the microscope lacked the high resolution we have come to expect in modern-day light microscopes. The images produced by the Hans’ primitive microscope was extremely blurry and had limited

High-index lenses are made from a substance that refracts more light than traditional lenses. This makes the lenses thinner and lighter.

A convex lens (with an index of refraction greater than the surrounding medium) causes the light from a given source on one side of the lens and passing through the lens to converge on the other side of the lens, forming an image at the focus. A concave lens with the same properties would cause that light to diverge, or spread out.

What we consider the modern microscope can be traced back to Holland in the 1590s. Hans and Zacharis Jensen, a father and son team of spectacles makers, are usually listed as the original inventors. Their microscope was simple by today’s standards; it included three sliding tubes with lens at both ends that opened up to eighteen inches when fully extended. The magnification power was generally considered to be about nine times. Even though the objects were magnified, they were blurry. Croft, the author of Under the Microscope: A Brief History of Microscopy, explains that the early devices had severe chromatic aberrations, which consist of color halos surrounding the object making clear viewing problematic. Over the course of the 17th and 18th centuries vast improvements occurred in the field of microscopy including magnification, size, and clarity. Microscopes were to become more portable, and less expensive allowing them to become a instrument commonly found in drawing

What conditions must exist for a converging lens to produce a real image of an object that is larger than the object itself?

Concave Lens: Concave lens is a diverging lens and are thinner in the middle. As rays of light travel through the lens, rays are spread out (diverge). When parallel rays of light passes through the lens, the refracted rays diverge and appear to come from one point called the principal focus. The distance between the distance between the principal focus and the centre of the lens is called the focal length.

Resolution is related to the numerical aperture of the objective lens – the higher the numerical aperture, the better the resolution; and the wavelength of light passing through the lens – the shorter the wavelength, the better the resolution.

Most microscopes, including those in schools and laboratories today, are optical microscopes. They use glass lenses to enlarge, or magnify, an image. An optical microscope cannot produce an image of an object smaller than the length of the light wave in use. To see anything smaller than 2,000 angstroms (about 1/250,000 of an inch) a wave of shorter length would

With today’s science, light becomes more specifically perceived as a spectrum. The specific name for this spectrum is the electromagnetic spectrum, which contains many types of waves (NASA, Electromagnetic Spectrum). In Figure 2, the spectrum shows a variety of wavelengths with specific wavelengths classified by its length. The range of wavelengths humans can see wavelengths that are around 400 – 700 nanometers (nm) as colors while all other electromagnetic waves are simply blind to humans. The interesting classes for light that are used to measure are microwave and infrared light. The laser is