How many types of lichens are there based on their external morphology (growth form)?

In the equation $\log\ S = \log\ C + Z\ \log\ A$,what does $C$ represent?

If one were to apply the Bohr model to a particle of mass $m$ and charge $q$ moving in a plane under the influence of a magnetic field $B$,the energy of the charged particle in the $n^{th}$ level will be:

Which of the following is a long-day plant?

The angle between the tangents drawn from the point $(1, 4)$ to the parabola ${y^2} = 4x$ is

In an $n-$type silicon,which of the following statements is true?