concave lens

biconcave lens

both B and C

convex lens

real, inverted and enlarged

virtual, upright and reduced

virtual, erect and enlarged

real, inverted and reduced

at a point half way to the focal point.

at the centre of curvature.

at infinity.

at the focal point.

X = centre of curvature, Y = optical centre, Z = focus

X = centre of curvature, Y = focus, Z = optical centre

X = focus, Y = optical centre, Z = centre of curvature

real, inverted and same size

real, inverted and diminished

virtual, erect and magnified

real, inverted and magnified

real, erect and magnified

more than its angle of incidence. 

less than its angle of incidence. 

can be more or less than its angle of incidence. 

the same as its angle of incidence. 

wavelength.

all of these.

frequency.

speed.

intensity

cool air.

warm air.

a vacuum.

travels slower in glass than in air. 

frequency is greater in glass than in air. 

travels at the same speed in air and in glass. 

frequency is greater in air than in glass.