X-rays and Lenses
- Created by: abbie.wilkinson
- Created on: 03-11-16 19:03
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- X-rays and Lenses
- X-rays
- We use x-rays in hospitals to take pictures and CT scans; they are also used to destroy tumours at or near the surface.
- X-rays are ionising, meaning that they have a lot of energy and so remove electrons from the atoms; this is damaging and can kill living cells.
- X-rays are part pf the electromagnetic spectrum.
- They have a high frequency and a short wavelength.
- Their wavelength is roughly the same size as the diameter of an atom.
- They have a high frequency and a short wavelength.
- X-rays are absorbed by bones and metal, and are transmitted by soft tissue.
- X-rays can be formed electronically using Charged-Coupled Devices (CCDs).
- Lenses
- A lens can be made of plastic or glass, and they can be made thinner by using a material with a higher refractive index.
- The thicker a converging lens is, the shorter the focal length.
- Because lenses refract light in a predictable way, then can be used for binoculars, cameras, glasses, and microscopes.
- There are two main types of lens: Converging (Convex) and Diverging (Concave)
- A converging lens makes parallel rays converge to a focus. The point where parallel rays are focused to is the principal focus (or focal point of the lens).
- A diverging lens makes parallel rays diverge (spread out). The point where the rays appear to come from is the principal focus of the lens.
- Rays coming into a lens from a distant object are almost parallel and form an image very close to the focus.
- Magnification = Image height divided by Object height
- A lens can be made of plastic or glass, and they can be made thinner by using a material with a higher refractive index.
- X-rays
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