Modern Physics PYQ — Page 5

In the following circuit, the reading of the ammeter will be (Take Zener breakdown voltage $=4 \mathrm{~V})$ 

A sub-atomic particle of mass $10^{-30} \mathrm{~kg}$ is moving with a velocity $2.21 \times 10^6 \mathrm{~m} / \mathrm{s}$. Under the matter wave consideration, the particle will behave closely like $\qquad$ $\left(\mathrm{h}=6.63 \times 10^{-34} \mathrm{~J} . \mathrm{s}\right)$

Choose the correct logic circuit for the given truth table having inputs A and B. $\begin{array}{|c|c|c|} \hline \text{Inputs} & & \text{Output} \\ \hline A & B & Y \\ \hline 0 & 0 & 0 \\ \hline 0 & 1 & 0 \\ \hline 1 & 0 & 1 \\ \hline 1 & 1 & 1 \\ \hline \end{array}$

The truth table corresponding to the circuit given below is 

An electron in the hydrogen atom initially in the fourth excited state makes a transition to $\mathrm{n}^{\text {th }}$ energy state by emitting a photon of energy 2.86 eV. The integer value of $n$ will be ____.

Arrange the following in the ascending order of wavelength $(\lambda)$ : (A) Microwaves $\left(\lambda_1\right)$ (B) Ultraviolet rays $\left(\lambda_2\right)$ (C) Infrared rays $\left(\lambda_3\right)$ (D) X-rays $\left(\lambda_4\right)$ Choose the most appropriate answer from the options given below :

The number of spectral lines emitted by atomic hydrogen that is in the $4^{\text {th }}$ energy level, is

During the transition of electron from state A to state C of a Bohr atom, the wavelength of emitted radiation is $2000 Å$ and it becomes $6000 Å$ when the electron jumps from state B to state C. Then the wavelength of the radiation emitted during the transition of electrons from state A to state B is

 For the circuit shown above, equivalent GATE is :

Which of the following circuits represents a forward biased diode?  Choose the correct answer from the options given below :

For a hydrogen atom, the ratio of the largest wavelength of Lyman series to that of the Balmer series is.

Energy released when two deuterons $\left({ }_1 \mathrm{H}^2\right)$ fuse to form a helium nucleus $\left({ }_2 \mathrm{He}^4\right)$ is : (Given : Binding energy per nucleon of ${ }_1 \mathrm{H}^2=1.1 \mathrm{MeV}$ and binding energy per nucleon of ${ }_2 \mathrm{He}^4=7.0 \mathrm{MeV}$)

A light source of wavelength $\lambda$ illuminates a metal surface and electrons are ejected with maximum kinetic energy of 2 eV . If the same surface is illuminated by a light source of wavelength $\frac{\lambda}{2}$, then the maximum kinetic energy of ejected electrons will be (The work function of metal is 1 eV )

The truth table for the circuit given below is : 

An electron with mass ' $m$ ' with an initial velocity $(\mathrm{t}=0) \overrightarrow{\mathrm{v}}=\mathrm{v}_0 \hat{\mathrm{i}} \quad\left(\mathrm{v}_0 \gt 0\right)$ enters a magnetic field $\vec{B}=B_0 \hat{j}$. If the initial de-Broglie wavelength at $\mathrm{t}=0$ is $\lambda_0$ then its value after time ' t ' would be :

Consider the following logic circuit.  The output is $\mathrm{Y}=0$ when :

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 found to be practically independent of the atomic number A, for nuclei with mass numbers between 30 and 170. Reason (R): Nuclear force is long range. In the light of the above statements, choose the correct answer from the options given below :

The frequency of revolution of the electron in Bohr's orbit varies with $n$, the principal quantum number as

If \(\lambda\) and \(K\) are de Broglie wavelength and kinetic energy, respectively, of a particle with constant mass. The correct graphical representation for the particle will be

Choose the correct nuclear process from the below options [p: proton, n : neutron, $\mathrm{e}^{-}$: electron, $\mathrm{e}^{+}$: positron, $v:$ neutrino, $\bar{v}$ : antineutrino]

Consider the following statements: A. The junction area of solar cell is made very narrow compared to a photo diode. B. Solar cells are not connected with any external bias. C. LED is made of lightly doped p-n junction. D. Increase of forward current results in continuous increase of LED light intensity. E. LEDs have to be connected in forward bias for emission of light. Choose the correct answer from the options given below:

The radiation pressure exerted by a 450 W light source on a perfectly reflecting surface placed at 2 m away from it, is :

A proton of mass ' $m_{\mathrm{p}}$ ' has same energy as that of a photon of wavelength ' $\lambda$ '. If the proton is moving at non-relativistic speed, then ratio of its de Broglie wavelength to the wavelength of photon is.

The truth table of the given circuit diagram is :