Assuming that the incident radiation is capable of ejecting photoelectrons from all the given metals,the lowest kinetic energy of the ejected photoelectron is observed with which of the given metals?

Chlorophyll in green plants absorbs light of frequency $4.620 \times 10^{14} \ Hz$. Find the wavelength and the region in the electromagnetic spectrum.

Mercury street lights emit light of a pale blue color with a wavelength of $436 \, nm$. Calculate its frequency.

Electromagnetic radiations of frequency $\nu$ consist of a stream of particles called photons. Which of the following statements is / are true about photons:

Wavelengths of different radiations are given below:
$\lambda(A) = 300 \ nm$
$\lambda(B) = 300 \ \mu m$
$\lambda(C) = 3 \ nm$
$\lambda(D) = 30 \ \mathring{A}$
Arrange these radiations in the increasing order of their energies.

Which parameter is indicated by the number of waves passing through a given point in one second?