# Optical Instrument

Card 1: Compound Microscope - Power of Lenses

## Compound Microscope - Power of Lenses

Power of Lens:
Power of Objective Lens > Power of Eyepiece

Io acts as the object of eyepiece

Card 2: Compound Microscope - Position of Object and Images

## Compound Microscope - Position of Object and Images

Position of Object:
Between Fo and 2Fo

Position of Image, Io:
Between Fe and Optical Centre of Eyepiece

Card 3: Compound Microscope - Nature of Images

## Compound Microscope - Nature of Images

Nature of image, Io:
Real, Inverted, Magnefied

Properties of image, Ie:
Virtual, Inverted, Magnefied

Card 4: Compound Microscope - Distance between the 2 lenses and Magnification

## Compound Microscope - Distance between the 2 lenses and Magnification

Distance between the 2 lenses:
Greater than fo + fe
fo = focal length of objective lens
fe = focal length of eyepiece

Magnification of Compound Microscope:

Card 5: Telescope - Power of Lenses

## Telescope - Power of Lenses

Power of Lens:
Power of Objective Lens < Power of Eyepiece

Io acts as the object of eyepiece

Card 6: Telescope - Position of Object and Images

## Telescope - Position of Object and Images

Position of Object:
Infinity

Position of Image, Io:
At the principle focus of the objective lens

Card 7: Telescope - Nature of Images

## Telescope - Nature of Images

Nature of image, Io:
Real, Inverted, Diminish (Smaller)

Properties of image, Ie:
Virtual, Inverted, Magnefied, form at infinity

Card 8: Telescope - Distance between the 2 Lenses and Magnification

## Telescope - Distance between the 2 Lenses and Magnification

Distance between the 2 lenses = fo + fe
fo = focal length of objective lens
fe = focal length of eyepiece

Magnification of Telescope:

Card 9: Projector - Slide and Projector Lens

## Projector - Slide and Projector Lens

Slide:

• As an object
• Is placed tilted at a distance between f and 2f from the projector lens.

Projector Lens:

• Projects an image on the screen that is placed a few meters from the projector lens.
• Can be adjusted to focus a sharp image.
Card 10: Projector - Condenser and Concave Mirror

## Projector - Condenser and Concave Mirror

Condenser:

• Consists of two Plano-convex lenses.
• Focuses all the light that brightens the whole slide.
• As a heat insulator to stop heat from the bulb so it does not spoil the slide.

Concave mirror:

• Reflects and focuses light that shines on it to the direction of the condenser.
Card 11: Projector - Nature of the Image

## Nature of the Image

The image formed by a projector is:

1. Real
2. Inverted
3. Magnified