Modern Physics PYQ — Page 14

The ratio of wavelengths of proton and deuteron accelerated by potential ${V}_{p}$ and ${V}_{d}$ is $1:\sqrt{2}$. Then, the ratio of ${V}_{p}$ to ${V}_{d}$ will be

The ratio for the speed of the electron in the ${3}^{\mathrm{rd}}$ orbit of ${\mathrm{He}}^{+}$ to the speed of the electron in the ${3}^{\mathrm{rd}}$ orbit of hydrogen atom will be :

In the circuit shown below, maximum Zener diode current will be _____ $\mathrm{mA}$. 

In the following nuclear reaction, $D\overset{\alpha }{\rightarrow }{D}_{1}\overset{{\beta }^{-}}{\rightarrow }{D}_{2}\overset{\alpha }{\rightarrow }{D}_{3}\overset{\gamma }{\rightarrow }{D}_{4}$ Mass number of $D$ is $182$ and atomic number is $74$ . Mass number and atomic number of ${D}_{4}$ respectively will be

The $Q$-value of a nuclear reaction and kinetic energy of the projectile particle, ${K}_{p}$ are related as

The equation $\lambda =\frac{1.227}{x}\mathrm{nm}$ can be used to find the de-Broglie wavelength of an electron. In this equation $x$ stands for : Where, $m=$ mass of electron $P=$ momentum of electron $K=$ Kinetic energy of electron $V=$ Accelerating potential in volts for electron

An $\alpha$ particle and a proton are accelerated from rest through the same potential difference. The ratio of linear momenta acquired by above two particals will be :

When light of frequency twice the threshold frequency is incident on the metal plate, the maximum velocity of emitted electron is ${v}_{1}$. When the frequency of incident radiation is increased to five times the threshold value, the maximum velocity of emitted electron becomes ${v}_{2}$. If ${v}_{2}=x{v}_{1}$, the value of $x$ will be _____ .

Read the following statements: (A) Volume of the nucleus is directly proportional to the mass number. (B) Volume of the nucleus is independent of mass number. (C) Density of the nucleus is directly proportional to the mass number. (D) Density of the nucleus is directly proportional to the cube root of the mass number. (E) Density of the nucleus is independent of the mass number. Choose the correct option from the following options.

The energy band gap of semiconducting material to produce violet (wavelength $=4000Å$) LED is _____ $\mathrm{eV}$. (Round off to the nearest integer).

$\sqrt{{d}_{1}}$ and $\sqrt{{d}_{2}}$ are the impact parameters corresponding to scattering angles $60^{\circ}$ and $90^{\circ}$ respectively, when an $\alpha$ particle is approaching a gold nucleus. For ${d}_{1}=x{d}_{2}$, the value of $x$ will be _____ .

A proton, a neutron, an electron and an $\alpha$-particle have same energy. If ${\lambda }_{p},{\lambda }_{n},{\lambda }_{e}$ and ${\lambda }_{\alpha }$ are the de Broglie's wavelengths of proton, neutron, electron and $\alpha$ particle respectively, then choose the correct relation from the following

A nucleus of mass $M$ at rest splits into two parts having masses $\frac{{M}^{'}}{3}$ and $\frac{2{M}^{'}}{3}({M}^{'}<M)$. The ratio of de Broglie wavelength of two parts will be

A beam of monochromatic light is used to excite the electron in ${\mathrm{Li}}^{++}$ from the first orbit to the third orbit. The wavelength of monochromatic light is found to be $x\times {10}^{-10}m$. The value of $x$ is _____ . [Given $hc=1242\mathrm{eV}\mathrm{nm}$]

Two lighter nuclei combine to form a comparatively heavier nucleus by the relation given below: $X12+X12=Y24$ The binding energies per nucleon $X12$ and $Y24$ are $1.1\mathrm{MeV}$ and $7.6\mathrm{MeV}$ respectively. The energy released in this process is_____ $\mathrm{MeV}$.

The electric field at a point associated with a light wave is given by $E=200[\mathrm{sin}(6\times {10}^{15})t+\mathrm{sin}(9\times {10}^{15})t]{\mathrm{Vm}}^{-1}$ Given: $h=4.14\times {10}^{-15}\mathrm{eVs}$ If this light falls on a metal surface having a work function of $2.50\mathrm{eV}$, the maximum kinetic energy of the photoelectrons will be

The photodiode is used to detect the optical signals. These diodes are preferably operated in reverse biased mode because

The de Broglie wavelengths for an electron and a photon are ${\lambda }_{e}$ and ${\lambda }_{p}$ 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?

A parallel beam of light of wavelength $900\mathrm{nm}$ and intensity $100{\mathrm{Wm}}^{-2}$ is incident on a surface perpendicular to the beam. The number of photons crossing $1{\mathrm{cm}}^{2}$ area perpendicular to the beam in one second is

Nucleus $A$ is having mass number $220$ and its binding energy per nucleon is $5.6\mathrm{MeV}$. It splits in two fragments $B$ and $C$ of mass numbers $105$ and $115$. The binding energy of nucleons in $B$ and $C$ is $6.4\mathrm{MeV}$ per nucleon. The energy $Q$ released per fission will be:

For using a multimeter to identify diode from electrical components, choose the correct statement out of the following about the diode

The light of two different frequencies whose photons have energies $3.8\mathrm{eV}$ and $1.4\mathrm{eV}$ respectively, illuminate a metallic surface whose work function is $0.6\mathrm{eV}$ successively. The ratio of maximum speeds of emitted electrons for the two frequencies respectively will be :

In a hydrogen spectrum $\lambda$ be the wavelength of first transition line of Lyman series. The wavelength difference will be "$a\lambda$" between the wavelength of ${3}^{\mathrm{rd}}$ transition line of Paschen series and that of ${2}^{\mathrm{nd}}$ transition line of Balmer Series where $a=$ _____.

Identify the logic operation performed by the given circuit