List of practice Questions

The kinetic energy of an electron having de-Broglie wavelength $\lambda $ is ( $h=$ Planck's constant, $m=$ mass of electron)
An $H$ -atom moving with speed $v$ makes a head-on collision with another $H$ -atom at rest. Both the atoms are in the ground state. The minimum value of velocity $v$ for which one of the atoms may excite is
If proton and a - particle are accelerated by the same potential $V$ . Then, the ratio of their wavelengths $\lambda _{\text{P}}:\lambda _{\alpha }$ would be
If the wavelenth of $K_{\alpha }$ radiation emitted by an atom of atomic number $Z=41$ is $\lambda $ , then the atomic number for an atom that emits $K_{\alpha }$ radiation with wavelength $4$ $\lambda $ , is
The energy (in $eV$ ) required to excite an electron from $n=2$ to $n=4$ state in hydrogen atom is
Two radioactive substances $A$ and $B$ have decay constants $5\lambda $ and $\lambda $ respectively. At $ \, t=0$ , a sample has the same number of the two nuclei. The time taken for the ratio of the number of nuclei to become $\left(\frac{1}{e}\right)^{2}$ will be
A $100$ watt bulb emits monochromatic light of wavelength $400\,nm$. Calculate the number of photons emitted per second by the bulb.
Electromagnetic waves were first of all produced in the laboratory by
The ratio of kinetic energy and the total energy of the electron in the $n^{th}$ quantum state of Bohr's atomic model of a hydrogen atom is
The wavelength of electromagnetic waves produced by Hertz was about
An electric charge in uniform motion produces
Electromagnetic waves are
If $ \mu_{0}$ be the permeability and $\varepsilon_{0} $ be the permittivity of a medium, then its refractive index is given by
Which among the following does not represent Maxwell's equation?
Hydrophs foetalis develops in case of defective alleles of two $\alpha$ -globin genes
In man which of the following genotypes and phenotypes may be the correct result of aneuploidy in sex chromosomes
Jacob's or criminal syndrome has a sex chromosome complement of
ZZ/ZW type of sex determination is seen in
How many geo-synchronous satellites are required to provide the communication over the whole part of the earth
In sickle cell anaemia 6-valine of $\beta$-chain forms hydrophobic bonds creating helical polymer of $\cdots\cdots\cdots\cdots\cdots$ strands
The requirement of transmitting microwaves from one position to another on the earth is that
Filters are essential components to
In optical fibre communication system, light source can be
Light emerging from the end of an optical fibre link must be detected and converted into electronic pulses for further processing so that
The height if geo-synchronous orbit from the surface of the earth is