Microscopy

Question 1

converging lens

Answer 1

• focus parallel rays of light into a single point of convergence
• the distance between the lens and that point is known as the focal length
• the point of convergence is known as the focal point

Question 2

diverging lens

Answer 2

• cause parallel rays of light to diverge
• for this reason the focal point is actually in front of the lens which means that objects look smaller than they actually are (demagnification)

Question 3

why do lenses bend light

Answer 3

known as refraction

• occurs when a beam of light moves from one medium to another at an angle other than 90 degrees
• light slows down as it enters another medium from air
• amount of bending or refraction depends on the refractive index
• greater the refractive index the slower the light travels
• refractive insect is ratio of velocity of light in a vacuum to velocity of light in the medium and is always greater than 1

Question 4

calculating refractions

Answer 4

n1sin1=n2sin2
n1= refractive index of original medium
sin1= angle at which the light rays enter the second medium
n2= refractive index of the second medium
sin2= angle at which the light rays passes through the second medium after being refracted

Question 5

the basics of magnification

Answer 5

traverse magnification

• occurs when an object is further away form the lens than its focal point
• the image produced is always inverted

angular magnification
- when an object is closer the the lens than its focal point a different form of magnification occurs

Question 6

converging lenses

Answer 6

real image formation
- object is further away form the lens that its focal point it forms a so called real image

virtual image

• when an object is nearer to the lens than its focal point forms a virtual image
• unlike real images, virtual images are not visible if we place a screen behind the lens

Question 7

angular magnification

Answer 7

simplest form of magnifier which consists of a biconvex lens or converging lens
- a magnifying lens allows us to bring subjects closer to the eye and remain in focus, the ye perceives the subject as if it were around 25cm hence the magnification

Question 8

the basics of magnification

Answer 8

subject is closer to the lens than the focal point size of the image in our retina increases as the subject and lens moves closer to the eye, when rays are traced back from the point of focus they diverge from a point on the same side of the lens as the object (virtual image)