Monochromatic light of frequency $6\times 10^{14}\mathrm{Hz}$ is produced by a laser. The power emitted is $2\times 10^{-3}\mathrm{W}$. How many photons per second on an average, are emitted by the source ? (Given $\mathrm{h}=6.63\times 10^{-34}\mathrm{Js}$ )

Conductivity of a photodiode starts changing only if the wavelength of incident light is less than $660\mathrm{nm}$. The band gap of photodiode is found to be $\left(\frac{\mathrm{X}}{8}\right)\mathrm{eV}$. The value of $\mathrm{X}$ is : (Given, $\mathrm{h}=6.6\times 10^{-34}\mathrm{Js},\mathrm{e}=1.6\times 10^{-19}\mathrm{C}$ )

The de Broglie wavelengths of a proton and an $\alpha$ particle are $\lambda$ and $2\lambda$ respectively. The ratio of the velocities of proton and $\alpha$ particle will be :

The threshold frequency of a metal with work function $$6.63\mathrm{eV}$$ is :

In a photoelectric effect experiment a light of frequency 1.5 times the threshold frequency is made to fall on the surface of photosensitive material. Now if the frequency is halved and intensity is doubled, the number of photo electrons emitted will be:

When a metal surface is illuminated by light of wavelength $$\lambda$$, the stopping potential is $$8\mathrm{V}$$. When the same surface is illuminated by light of wavelength $$3\lambda$$, stopping potential is $$2\mathrm{V}$$. The threshold wavelength for this surface is:

The de-Broglie wavelength of an electron is the same as that of a photon. If velocity of electron is $$25\%$$ of the velocity of light, then the ratio of K.E. of electron and K.E. of photon will be:

Two sources of light emit with a power of $$200\mathrm{W}$$. The ratio of number of photons of visible light emitted by each source having wavelengths $$300\mathrm{nm}$$ and $$500\mathrm{nm}$$ respectively, will be :

For the photoelectric effect, the maximum kinetic energy $$\left(E_k\right)$$ of the photoelectrons is plotted against the frequency $$(v)$$ of the incident photons as shown in figure. The slope of the graph gives

If the total energy transferred to a surface in time $$\mathrm{t}$$ is $$6.48\times 10^5\mathrm{J}$$, then the magnitude of the total momentum delivered to this surface for complete absorption will be:

The work function of a substance is $$3.0\mathrm{eV}$$. The longest wavelength of light that can cause the emission of photoelectrons from this substance is approximately;

UV light of $$4.13\mathrm{eV}$$ is incident on a photosensitive metal surface having work function $$3.13\mathrm{eV}$$. The maximum kinetic energy of ejected photoelectrons will be:

A proton, an electron and an alpha particle have the same energies. Their de-Broglie wavelengths will be compared as :

Which figure shows the correct variation of applied potential difference (V) with photoelectric current (I) at two different intensities of light $$(\mathrm{I}_1

Given below are two statements: one is labelled as Assertion $$\mathbf{A}$$ and the other is labelled as Reason R. Assertion A: Number of photons increases with increase in frequency of light. Reason R: Maximum kinetic energy of emitted electrons increases with the frequency of incident radiation. In the light of the above statements, choose the most appropriate answer from the options given below:

A proton and an electron have the same de Broglie wavelength. If $${\mathrm{K}}_{\mathrm{p}}$$ and $${\mathrm{K}}_{\mathrm{e}}$$ be the kinetic energies of proton and electron respectively, then choose the correct relation :

A proton and an electron are associated with same de-Broglie wavelength. The ratio of their kinetic energies is: (Assume h = 6.63 $$\times 10^{-34}\mathrm{J}\mathrm{s},{\mathrm{m}}_{\mathrm{e}}=9.0\times 10^{-31}\mathrm{kg}$$ and $${\mathrm{m}}_{\mathrm{p}}=1836$$ times $${\mathrm{m}}_{\mathrm{e}}$$ )

Given below are two statements : Statement I : Figure shows the variation of stopping potential with frequency $$(v)$$ for the two photosensitive materials $$M_1$$ and $$M_2$$. The slope gives value of $$\frac{h}{e}$$, where $$h$$ is Planck's constant, e is the charge of electron. Statement II : $${\mathrm{M}}_2$$ will emit photoelectrons of greater kinetic energy for the incident radiation having same frequency. In the light of the above statements, choose the most appropriate answer from the options given below.

Which of the following statement is not true about stopping potential $$({\mathrm{V}}_0)$$ ?

When UV light of wavelength $$300\mathrm{nm}$$ is incident on the metal surface having work function $$2.13\mathrm{eV}$$, electron emission takes place. The stopping potential is : (Given hc $$=1240\mathrm{eV}\mathrm{nm}$$ )