Ans these q
Dear student
a)Optical density (OD) of a medium is the measure of its transmittance for a radiation of particular wavelength. Higher is the value of OD, lower is transmittance. It is expressed as log10 (1/T), where T is the transmittance in percentage.OD is related to refractive index of a material. A higher value of refractive index means higher OD. This means that light travels slower, in a medium with high optical density.
b)
a)Optical density (OD) of a medium is the measure of its transmittance for a radiation of particular wavelength. Higher is the value of OD, lower is transmittance. It is expressed as log10 (1/T), where T is the transmittance in percentage.OD is related to refractive index of a material. A higher value of refractive index means higher OD. This means that light travels slower, in a medium with high optical density.
b)
The minimum number of rays required for locating the image formed by any mirror for an object is 2.
Formation of virtual image by concave mirror:
Regards