, Definition of Principal focus (Focal Point) - CORRECT ANSWERS-The point through
which all light parallel to the axis of the lens passes through
Definition of Focal length - CORRECT ANSWERS-The distance between the centre of
the lens and the focal point.
Formation of images by converging lenses
object beyond 2f - CORRECT ANSWERS-image upside down, small
Formation of images by converging lenses
object between F and lens - CORRECT ANSWERS-image behind lens, upright, small
Ray diagram of a refracting telescope in normal adjustment - CORRECT ANSWERS-
Angular magnification in normal adjustment - CORRECT ANSWERS-Angular
magnification = B/a = fo/fe
B- angle to image
a- angle to object
Cassegrain Telescope - CORRECT ANSWERS-
Definition spherical aberration - lens - CORRECT ANSWERS-Where parallel rays at
different distances from principal axis are brought to focus at different points (on
principal axis). Due to non-parabolic mirror
How to solve spherical aberration - CORRECT ANSWERS-Use a parabolic mirror.
Diagram of spherical aberration of a mirror - CORRECT ANSWERS-rays further from
principal axis are focused to a point closer to mirror
Effect on image of spherical aberration - CORRECT ANSWERS-Image is blurred
Definition chromatic aberration - CORRECT ANSWERS-Where different wavelengths
are refracted by different amounts resulting in different focal lengths for different
wavelengths (colours).
Effect on image of chromatic aberration - CORRECT ANSWERS-Images have
multicoloured, blurred edges
Chromatic aberration - CORRECT ANSWERS-blue light (shorter wavelengths) are
focused closer to lens that red light (longer wavelengths)
Minimum angular resolution
which all light parallel to the axis of the lens passes through
Definition of Focal length - CORRECT ANSWERS-The distance between the centre of
the lens and the focal point.
Formation of images by converging lenses
object beyond 2f - CORRECT ANSWERS-image upside down, small
Formation of images by converging lenses
object between F and lens - CORRECT ANSWERS-image behind lens, upright, small
Ray diagram of a refracting telescope in normal adjustment - CORRECT ANSWERS-
Angular magnification in normal adjustment - CORRECT ANSWERS-Angular
magnification = B/a = fo/fe
B- angle to image
a- angle to object
Cassegrain Telescope - CORRECT ANSWERS-
Definition spherical aberration - lens - CORRECT ANSWERS-Where parallel rays at
different distances from principal axis are brought to focus at different points (on
principal axis). Due to non-parabolic mirror
How to solve spherical aberration - CORRECT ANSWERS-Use a parabolic mirror.
Diagram of spherical aberration of a mirror - CORRECT ANSWERS-rays further from
principal axis are focused to a point closer to mirror
Effect on image of spherical aberration - CORRECT ANSWERS-Image is blurred
Definition chromatic aberration - CORRECT ANSWERS-Where different wavelengths
are refracted by different amounts resulting in different focal lengths for different
wavelengths (colours).
Effect on image of chromatic aberration - CORRECT ANSWERS-Images have
multicoloured, blurred edges
Chromatic aberration - CORRECT ANSWERS-blue light (shorter wavelengths) are
focused closer to lens that red light (longer wavelengths)
Minimum angular resolution
