List of top Physics Questions on Dual nature of matter

A convex lens of focal length 40 cm forms an image of an extended source of light on a photo-electric cell. A current \( I \) is produced. The lens is replaced by another convex lens having the same diameter but focal length 20 cm. The photoelectric current now is:

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

If the momentum of an electron is changed by P, then the de Broglie wavelength associated with it changes by\( 1\%\). The initial momentum of the electron will be:

If the energy of incident radiation is increased by $25\%$, the kinetic energy of the photoelectrons emitted increases from 0.6 eV to 0.9 eV. The work function of the metal is:

When a photon of energy hν falls on a photosensitive metallic surface (work function hν0), electrons are emitted from the metallic surface. It is possible to say that:

In a Young’s double-slit experiment using monochromatic light of wavelength λ, the intensity of light In a Young’s double-slit experiment, using mono chromatic light of wave length λ, the intensity of light at a point on the screen is I₀, where the path difference between the interfering waves is λ. The path difference between the interfering waves at a point where the intensity is \(\frac{I_o}{2}\) , will be:at a point on the screen is I0​, where the path difference between the interfering waves is λ. The path difference at a point where the intensity is 2I0​​ will be:

A proton accelerated through a potential difference V has a de Broglie wavelength λ. On doubling the accelerating potential, the de Broglie wavelength of the proton_____.
Fill in the blank with the correct answer from the options given below

A point source causing photoelectric emission from a metallic plate is moved away from the plate. The variation of photoelectric current with distance from the source is correctly represented by the graph ______.
Fill in the blank with the correct answer from the options given below

Radiation of frequency \(2ν_0\) is incident on a metal with threshold frequency \(ν_0\). The correct statement of the following is ______.

If all the particles have same kinetic energy, The relation between the wavelengths of alpha particle, electron and proton is:

The kinetic energy of an electron, α-particle and a proton are given as 4K, 2K and K respectively. The de-Broglie wavelength associated with electron (λe) α-particle (λα) and the proton (λp) are as follows :

α-particle, proton & electron have same kinetic energy. Select correct order of their de-Broglie wavelength.

The de Broglie wavelengths for an electron and a photon are λ_e and λ_p, respectively. For the same kinetic energy of electron and photon, which of the following presents the correct relation between the de Broglie wavelengths of two?

In a photoemission experiment, the maximum kinetic energies of photoelectrons from metals P, Q and R are E_P, E_Q and E_R, respectively, and they are related by E_P = 2E_Q = 2E_R. In this experiment, the same source of monochromatic light is used for metals P and Q while a different source of monochromatic light is used for metal R. The work functions for metals P, Q and R are 4.0 eV, 4.5 eV and 5.5 eV, respectively. The energy of the incident photon used for metal R, in eV, is ___.

Light with an average flux of $20\,\Omega/cm^2$ falls on a non-reflecting surface at normal incidence having surface area $20\,cm^2$. The energy received by the surface during time span of $1\,minute$ is :

Light of frequency 1.5 times the threshold frequency is incident on a photosensitive material. What will be the photoelectric current if the frequency is halved and intensity is doubled?

An electron is accelerated from rest through a potential difference of V volt. If the de Broglie wavelength of the electron is $1.227 \times 10^{-2}nm$, the potential difference is :

An example for the best source of monochromatic light is

An electron is accelerated through a potential difference of 10,000 V. Its de Broglie wavelength is. (nearly): (mt. = $9 \times 10^{-31}$ kg)

If the kinetic energy of a free electron doubles, it�s de-Broglie wavelength changes by the factor

When the light of frequency $2v_0$ (where $v_0$ is threshold frequency), is incident on a metal plate, the maximum velocity of electrons emitted is $v_1$. When the frequency of the incident radiation is increased to $5v_0$, the maximum velocity of electrons emitted from the same plate is $v_2$. The ratio of $v_1$ to $v_2$ is

An electron of mass $m$ with an initial velocity $\vec{V} = V_0 \hat{i} (V_0 > 0)$ enters an electric field $\vec{E} = - E_0 \hat{i} (E_0 = \text{constant } > 0)$ at $t = 0$. If $\lambda_o$ is its de-Broglie wavelength initially,. then its de-Broglie wavelength at time $t$ is

If the X-ray tube is working at 20 kV then the minimum wavelength of X-rays will be