Dual Nature Of Radiation - Modern Physics - Physics Previous Year Questions

An electron is moving with an initial velocity \(\mathbf{v}=v_0 \hat{\mathbf{i}}\) and is in a uniform magnetic field \(\mathbf{B}=B_0 \hat{\mathbf{j}}\). Then its de-Broglie wavelength

Light of certain frequency and intensity incident on a photosensitive material causes photoelectric effect. If both the frequency and intensity are doubled, the photoelectric saturation current becomes

The de-Broglie wavelength associated with electron of hydrogen atom in this ground state is

A hot filament liberates an electron with zero initial velocity. The anode potential is \(1200 \mathrm{~V}\). The speed of the electron when it strikes the anode is

The following graph represents the variation of photocurrent with anode potential for a metal surface. Here \(I_1, I_2\) and \(I_3\) represents intensities and \(\gamma_1, \gamma_2, \gamma_3\) represent frequency for curves \(1,2\) and \(3\) respectively, then

A proton moving with a momentum \(p_1\) has a kinetic energy \(1 / 8\)th of its rest mass-energy. Another light photon having energy equal to the kinetic energy of the possesses a momentum \(p_2\). Then, the ratio \(\frac{p_1-p_2}{p_1}\) is equal to

According to Einstein's photoelectric equation to the graph between kinetic energy of photoelectrons ejected and the frequency of incident radiation is

The work-function of a metal is 1 eV. Light of wavelength \(3000 \mathop A\limits^o\) is incident on this metal surface. The velocity of emitted photoelectrons will be

The kinetic energy of the photoelectrons increases by \(0.52 \mathrm{~eV}\) when the wavelength of incident light is changed from \(500 \mathrm{~nm}\) to another wavelength which is approximately

In a photo electric experiment, if both the intensity and frequency of the incident light are doubled, then the saturation photoelectric current

The de-Broglie wavelength of a particle of kinetic energy \(K\) is \(\lambda\), the wavelength of the particle, if its kinetic energy \(\frac{K}{4}\) is

In an experiment to study photoelectric effect the observed variation of stopping potential with frequency of incident radiation is as shown in the figure. The slope and \(y\)-intercept are respectively

The energy gap of an LED is \(2.4 \mathrm{~eV}\). When the LED is switched ON, the momentum of the emitted photons is

A 60 W source emits monochromatic light of wavelength 662.5 nm. The number of photons emitted per second is

The photoelectric work function for photo metal is 2.4 eV . Among the four wavelengths, the wavelength of light for which photoemission does not take place is