From the following graph of photo-current against collector plate potential,for two different intensities of light $I_{1}$ and $I_{2}$,one can conclude:

The figure shows the variation of photocurrent with anode potential for a photo-sensitive surface for three different radiations. Let ${I_a}, {I_b}$ and ${I_c}$ be the intensities and ${f_a}, {f_b}$ and ${f_c}$ be the frequencies for the curves $a, b$ and $c$ respectively.

When the distance of a light source from a photocell is $r_1$,the photoelectric current is $I_1$. If the distance is $r_2$,the photoelectric current becomes $I_2$. The ratio $(I_1 : I_2)$ is .....

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A :$ In photoelectric effect,on increasing the intensity of incident light,the stopping potential increases.
Reason $R :$ Increase in intensity of light increases the rate of photoelectrons emitted,provided the frequency of incident light is greater than threshold frequency.
In the light of the above statements,choose the correct answer from the options given below:

The work function of aluminium is $4.2 \ eV$. If two photons, each of energy $3.5 \ eV$, strike an electron of aluminium, then the emission of electrons will be:

In a photoelectric experiment,increasing the intensity of incident light :