List of top Physics Questions on Modern Physics

Which statistical distribution describes the behavior of identical, indistinguishable particles with half-integral spin?
According to the Special Theory of Relativity, what happens to the length of an object as its velocity approaches the speed of light?
What is the energy of the ground state of a hydrogen atom according to the Bohr model?
What is the de Broglie wavelength of an electron accelerated through a potential difference of \(V\) volts?
Find out the correct energy for the ground state or energy transition. (Symbols have usual meaning and \(n \to m\) gives the transition)
For the given set of measurements, find the relative error. \[ 20.00,\ 19.75,\ 18.25,\ 17.01 \]
Find number of photons emitted per second by a light source of wavelength \(663\,\text{nm}\) at power \(6\,\text{mW}\). If \(h = 6.63 \times 10^{-34}\,\text{Js}\) is \(N \times 10^{15}\), then find \(N\).
Find de-Broglie wavelength of an oxygen molecule at $27^\circ$C. Molar mass of oxygen molecule is $32$ g/mole.
Which of the following material has bigger Young's modulus?
Given below are two statements:
Statement (I): The dimensions of Planck's constant and angular momentum are same.
Statement (II): In Bohr's model, electrons revolve around the nucleus only in those orbits for which angular momentum is an integral multiple of Planck's constant.
In the light of the above statements, choose the most appropriate answer from the options given below:
If the electric field of EM wave is given by \( 60 \sin(3 \times 10^{14}t) + \sin(12 \times 10^{14}t) \) at \( x = 0 \) falls on a photo sensitive material having work function 2.8 eV. Find the maximum kinetic energy (in eV) of ejected electrons.
On two metal surfaces, a monochromatic light of $6 \text{ eV}$ was incident. They have ratio of their work function and maximum KE as $\frac{\Phi_1}{\Phi_2} = \frac{1}{2}$ and $\frac{(KE_{\max})_1}{(KE_{\max})_2} = \frac{2.62}{1}$. Then $\Phi_1$ and $\Phi_2$ values are respectively (in $\text{eV}$).
When electromagnetic radiation of wavelength 310 nm falls on the surface of a metal having work function 3.55 eV, the velocity of photoelectrons emitted is \( x \times 10^5 \text{ms}^{-1} \). The value of \( x \) is (Nearest integer) (\( m_e = 9 \times 10^{-31} \text{kg} \))
An electromagnetic radiation of wavelength 331.5 nm is made to strike the surface of a metal. Electrons are emitted with a kinetic energy of \(1.2 \times 10^5\) J mol\(^{-1}\). The work function (in eV) of the metal is (h=\(6.63 \times 10^{-34}\) Js, \(N_A = 6 \times 10^{23}\) mol\(^{-1}\))
If the total energy of an electron in an orbit is positive, then
The work done to accelerate an electron from rest so that it can have a de Broglie wavelength of 6600 Å is nearly (Planck's constant = \(6.6 \times 10^{-34}\) Js and mass of electron = \(9 \times 10^{-31}\)kg)
Match the "Technology" given in List-1 with the "Principle of Physics" given in List-2.
If the difference in the frequencies of the first and second lines of Lyman series of hydrogen atom is f, then the difference in frequencies of the first and second lines of Balmer series of hydrogen atom is
Photons of energy 4.5 eV are incident on a photosensitive material of work function 3 eV. The de Broglie wavelength associated with the photoelectrons emitted with maximum kinetic energy is nearly
For any fixed distance, the electromagnetic force between two protons is \( 10^n \) times of the gravitational force between them. Then \( n = \)
Identify the incorrect statement from the following?
In $\beta^-$ decay, a neutron transforms into a proton within the nucleus according to the equation:
neutron $\to$ proton + $\beta^-$ + $x$
In this equation the particle represented by 'x' is
An electron in n-region of a p-n junction moves towards the junction with a speed of \(5 \times 10^5\ \text{ms}^{-1}\). If the barrier potential of the junction is \(0.45\ \text{V}\), then the speed with which the electron enters the p-region after penetration through the barrier is
(Charge of the electron \(= 1.6 \times 10^{-19}\ \text{C}\) and mass of the electron \(= 9 \times 10^{-31}\ \text{kg}\))
Coaxial cable, a widely used wire medium offers an approximate frequency bandwidth of
\(10^{10}\) electrons enter the emitter of a junction transistor in a time of \(0.4\ \mu\text{s}\). If \(5%\) of the electrons are lost in the base, then the collector current is