Name the device used for measuring the mass of atoms and molecules.

Consider the following statements: $(1)$ Both wave and particle nature are required for a complete understanding of light. $(2)$ Light cannot exhibit both wave and particle nature simultaneously in a single experiment.

The anode voltage of a photocell is kept fixed. The wavelength $\lambda$ of the light falling on the cathode is gradually changed. The plate current $I$ of the photocell varies as follows:

Statement $(I)$ : By increasing the potential difference between cathode and anode continuously in a photoelectric experiment,the photocurrent always increases continuously.
Statement $(II)$ : If two photons $A$ and $B$ of energies $2.5 \ eV$ and $3.5 \ eV$ respectively fall on a metal surface of work function $2.0 \ eV$,then the ratio of maximum kinetic energies emitted between $A$ and $B$ is $3$.
Statement $(III)$ : The maximum energy needed by an electron to come out from metal surface is called the work function of the metal.
Which of the following is correct?

Match List-$I$ (Fundamental Experiment) with List-$II$ (its conclusion) and select the correct option from the choices given below the list.

List-$I$	List-$II$
$a$. Franck-Hertz Experiment	$i$. Particle nature of light
$b$. Photo-electric Experiment	$ii$. Discrete energy levels of atom
$c$. Davisson-Germer Experiment	$iii$. Wave nature of electron
	$iv$. Structure of atom

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