Modern Physics PYQ — Page 10

A proton moving with one tenth of velocity of light has a certain de Broglie wavelength of $\lambda$. An alpha particle having certain kinetic energy has the same de-Brogle wavelength $\lambda$. The ratio of kinetic energy of proton and that of alpha particle is :

If $917Å$ be the lowest wavelength of Lyman series then the lowest wavelength of Balmer series will be $Å$.

If the binding energy of ground state electron in a hydrogen atom is $13.6\mathrm{eV}$, then, the energy required to remove the electron from the second excited state of $\mathrm{Li}{}^{2+}$ will be: $x\times {10}^{-1}\mathrm{eV}$. The value of $x$ is _____.

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R Assertion A: Photodiodes are used in forward bias usually for measuring the light intensity. Reason R: For a $p-n$ junction diode, at applied voltage $V$ the current in the forward bias is more than the current in the reverse bias for $|{V}_{z}|>\pm V\geq |{V}_{0}|$ where ${V}_{0}$ is the threshold voltage and ${V}_{z}$ is the breakdown voltage. In the light of the above statements, choose the correct answer from the options given below

A zener diode of power rating $1.6W$ is to be used as voltage regulator. If the zener diode has a breakdown of $8V$ and it has to regulate voltage fluctuating between $3V$ and $10V$ The value of resistance ${R}_{s}$ for safe operation of diode will be 

A light of energy $12.75\mathrm{eV}$ is incident on a hydrogen atom in its ground state. The atom absorbs the radiation and reaches to one of its excited states. The angular momentum of the atom in the excited state is $\frac{x}{\pi }\times {10}^{-17}\mathrm{eVs}$. The value of $x$ is ______ (use $h=4.14\times {10}^{–15}\mathrm{eVs},c=3\times {10}^{8}m{s}^{–1}$)

The resistivity $(\rho )$ of semiconductor varies with temperature. Which of the following curve represents the correct behaviour?

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A : The binding energy per nucleon is practically independent of the atomic number for nuclei of mass number in the range $30$ to $170$. Reason R : Nuclear force is short ranged. In the light of the above statements, choose the correct answer from the options given below

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A: Diffusion current in a $p-n$ junction is greater than the drift current in magnitude if the junction is forward biased. Reason R: Diffusion current in a $p-n$ junction is form the $n$-side to the $p$-side if the junction is forward biased. In the light of the above statements, choose the most appropriate answer from the options given below.

The ratio of the density of oxygen nucleus $(O816)$ and helium nucleus $(\mathrm{He}24)$ is

Name the logic gate equivalent to the diagram attached 

Choose the correct statement about Zener diode:

The de Broglie wavelength of an electron having kinetic energy $E$ is $\lambda$. If the kinetic energy of electron becomes $\frac{E}{4}$, then its de-Broglie wavelength will be:

The ratio of wavelength of spectral lines ${H}_{\alpha }$ and ${H}_{\beta }$ in the Balmer series is $\frac{x}{20}$. The value of $x$ is _____.

A point source of $100W$ emits light with $5%$ efficiency. At a distance of $5m$ from the source, the intensity produced by the electric field component is:

The radius of electron's second stationary orbit in Bohr's atom is $R$. The radius of ${3}^{rd}$ orbit will be

$92238A\rightarrow 90234B+D24+Q$ In the given nuclear reaction, the approximate amount of energy released will be: [Given, mass of $92238A=238.05079\times 931.5\mathrm{MeV}{c}^{-2}$, mass of $B90234=234.04363\times 931.5\mathrm{MeV}{c}^{-2}$, mass of $D24=4.00260\times 931.5\mathrm{Me}V{c}^{-2}$ ]

If each diode has a forward bias resistance of $25\Omega$ in the below circuit,  Which of the following options is correct?

The output $Y$ for the inputs $A$ and $B$ of circuit is given by  Truth table of the shown circuit is :

Proton $(P)$ and electron $(e)$ will have same de-Broglie wavelength when the ratio of their momentum is (assume, ${m}_{p}=1849$ ${m}_{e}$)

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R Assertion A : The nuclear density of nuclides $B510,L36i,F2656e,N1020e\text{and}B83209i$ can be arranged as ${\rho }_{Bi}^{N}>{\rho }_{Fe}^{N}>{\rho }_{Ne}^{N}>{\rho }_{B}^{N}>{\rho }_{Li}^{N}$ Reason R : The radius $R$ of nucleus is related to its mass number $A$ as $R={R}_{0}{A}^{\frac{1}{3}}$, where ${R}_{0}$ is a constant. In the light of the above statement, choose the correct answer from the options given below :

From the photoelectric effect experiment, following observations are made. Identify which of these are correct A. The stopping potential depends only on the work function of the metal. B. The saturation current increases as the intensity of incident light increases. C. The maximum kinetic energy of a photo electron depends on the intensity of the incident light. D. Photoelectric effect can be explained using wave theory of light. Choose the correct answer from the options given below:

The kinetic energy of an electron, $\alpha -$particle and a proton are given as $4K,2K$ and $K$ respectively. The de-Broglie wavelength associated with electron $({\lambda }_{e}),\alpha -$particle $({\lambda }_{\alpha })$ and the proton $({\lambda }_{p})$ are as follows:

The variation of stopping potential $({V}_{0})$ as a function of the frequency $(\nu )$ of the incident light for a metal is shown in figure. The work function of the surface is