5.5.6 Slide Projector

Posted on April 17, 2020 by user

Bulb	Bulb with high brightness is used. The bulb must be placed at the centre of curvature of the concave mirror.
Concave mirror	The function of the concave mirror is to reflect and focus light that shines on it to the direction of the condenser. This is to increase the brightness of the image.
Condenser	The condenser consists of two Plano-convex lenses. The function of the condenser is to focus all the light that brightens the whole slide. It also acts as a heat insulator to stop heat from the bulb so it does not spoil the slide.
Slide	The slide acts as the object. It is located at a distance between f and 2f from the projector lens so that the image produced is real and magnified. It is purposely placed upside down so that the image forms on the screen looks upright.
Projector Lens	The projector lens projects the image on the screen that is placed a few meters away. It can be adjusted to focus a sharp image.
Image	The image produced is real (it form on a screen) magnified inverted (Since the slide is placed upside down, hence the image looks upright)

5.5.5 Camera

Posted on April 17, 2020 by user

Convex lens	To focus the light of an object onto the film so that a sharp image can be produced.
Diaphragm	To control the size of the aperture and hence control the amount of light move into the camera.
Focusing Ring	To adjust the distance between the lens and the film so that the image is sharply focus on the film.
Film	Acts as a screen for the image to form onto it. Chemical on it will react when exposed to light and produce a photograph.
Shutter	Open when picture is taken to allow light move onto the film. The shutter speed is the length of time when the shutter is open. It control the amount of light move onto the film.
Aperture	Open when picture is taken to allow light move onto the film. The shutter speed is the length of time when the shutter is open. It control the amount of light move onto the film.

The film, which is normally kept in total darkness, contains a light-sensitive chemical called silver bromide.
When you press the camera button, a shutter in front of the film opens then shuts again, exposing the film to light for a brief moment only.
Different intensities and colours of light across the image cause varying chemical changes in the film, which can later be developed, 'fixed', and used in printing a photograph.
The image formed on the film is
1. Real
2. Inverted
3. Smaller than the object.

Posted on April 17, 2020 by user

	Compound Microscope
Object lens	Higher power
Eye lens	Lower power
Position of the object	The object is placed at a position between fo and 2fo.
Nature of the image, I₁	Real, inverted and magnified
Position of the image, I₁.	The first image, I1 must be placed between the optical center of the eye lens with the eye lens principle focus point, fe.
Nature of the image, I₂	Virtual, inverted and magnified
Distance in between the two lens	The distance between the object lens and the eye lens in a compound microscope is bigger than the sum of the focal length (f_o + f_e). If the distance between both lenses are adjusted to less than (f_o + f_e), no image can be seen.
Magnification of the compound microscope.	m₁ = Linear magnification of the object lens m₂ = Linear magnification of the object lens

Posted on April 17, 2020 by user

	Astronomical Telescope
Objective lens	Lower power
Eye lens	Higher power
Position of the object	At infinity
Nature of the image, I₁	Real, inverted and magnified
Position of the image, I₁.	At the principle focus of object lens, fo.
Nature of the image, I₂	Virtual, inverted and smaller in size.
Distance in between the two lens	The distance between the object lens and the eye lens in a compound microscope is equal to the sum of the focal length (f_o + f_e). If the distance between both lenses are bigger than (f_o + f_e), no image can be seen.
Magnification of the compound microscope.

Posted on April 17, 2020 by user

Magnifying glass is also known as simple microscope.
A magnifying glass is a single convex lens with short focal length.
The iage formed is
1. virtual,
2. magnified
3. upright
A magnifying glass enlarges the image of an object by increasing the virtual angle at the eye when the object is viewed.

Posted on April 17, 2020 by user

The angular magnitude of an object is the virtual angle at the eye. It is the angle the object subtends at the eye.
This angle determines the size of the image (apparent size) formed on the retina and hence governs the apparent size of the object

Posted on April 17, 2020 by user

The following is the lens equation that relates the object distance (u), image distance (v) and the focal length.
When using the lens equation to solve problem, it's important to note the positive negative sign of u, v and f.
Table below give the conventional symbol and sign for u, v and f.

Posted on April 17, 2020 by user

The linear magnification is a quantity that indicates the ratio of the height of the image to the height of the object.

m = linear magnification
u = distance of object
v = distance of image
h_i = heigth of image
h_o = heigth of object

Posted on April 17, 2020 by user

The image formed by a concave lens always has the same characteristics, namely
1. virtual
2. upright
3. diminish
Figure below shows the ray diagram for the formation of image of a concave lens.

Posted on April 17, 2020 by user

As with a curved mirror, the position and size of an image can be found by drawing a ray diagram.
Any two of the following three rays are sufficient to fix the position and size of the image.
The characteristics, position and size of the image formed by a convex lens depends on the object distance (u) relative to the focal length (f)

Characteristics of the Image: Real, inverted, diminish
Distance of image: v < 2f

Characteristics of the Image: Real, inverted, same size
Distance of image: v = 2f

Characteristics of the Image: Real, inverted, magnified
Distance of image: v > 2f

Characteristics of the Image: -
Distance of image: At infinity

Characteristics of the Image: Virtual, uprigh, magnified
Position of image: at the same side of the object