Geometrical Optics Flashcards
What is a lens ?
A piece of Transparent material that can focus a transmitted beam of light
What are two types of lenses ?
🥱convex / converging lens
🥱 diverging/ concave lens
The point f to which the rays are brought to focus is called?
Principal focus or focal point
Distance between optical centre and its principle focus is called
Focal length
Convex lens gives
Real image
Concave gives
Virtual images
Real Images are always ?
Inverted
Virtual images are always ?
Errect
What is Visual angle ?
The apparent size of the object depends upon angle substanted by the eye
Least distance of distinct vision is?
25cm
A type of convex lens which brings object closer is called ?
Magnifying 🔍 glass
An optical instrument which is used to see small object with very high magnification is called ?
Compound microscope 🔬
Image formed by compound microscope is ?
Virtual and very much magnified
Optical instrument used to see distant object and heavenly bodies that is planets and stars is called ?
Astronomical telescope
Image formed by astronomical telescope is ?
Highly magnified / inverted / virtual
Distance between objective and eye piece 🧩 is called ?
Length of telescope 🔭
An instrument used to see objects on earth is called
Galilean Telescope
Instrument which is used to study the spectrum of luminous bodies is called?
Spectrometer
The front of eye is covered by transparent membrane called?
Cornea
Muscular diaphragm that control the size of pupil ?
Iris
When images formed behind retina … The Abnormality is ?
✓ Myopia ( far sighted )
✓corrected by using converging lens
When image is formed Infront of retina … The Abnormality is known as ?
✓Hyperopia or short sightedness
✓ corrected by using diverging lens
Bright sunlight is an example of ?
Convex lens
When the magnification of a lens is less than 1 , it means the image is actually :
M(Dec) q (Dec )
Smaller than obj
Smaller the distance of object from the eye 👁️ the visual angle will be ?
Visual angle ( inc ) distance (Dec)
Greater
Linear magnification produced by a lens is defined as :
The ratio of size of image to size of object
