a) Current is given as I = V/R from the Ohm’s law Therefore, I = 1A But, I = ne Avd vd = I/neA When the values for the above parameters are substituted, vd = 1/1.6 × 10-4 m/s The KE = (KE of one...
a) Consider the circuit in the figure. How much energy is absorbed by electrons from the initial state of no current to the state of drift velocity? b) Electrons give up energy at the rate of RI2 per second to the thermal energy. What time scale would one associate with energy in problem a) n = no of electron/volume = 1029/m3, length of circuit = 10 cm, cross-section = A = 1mm2
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(b) 
(c) 
(d) 
is modified to 
Calculate in such a case, the ground state energy of an 
atom, if 
for the force between an electron and a proton. The 
dependence of 
can be understood in quantum theory as being due to the fact that the ‘particle’ of light (photon) is massless. If photons had a mass 
, force would be modified to ![|F|=\frac{e^{2}}{\left(4 \pi \epsilon_{0}\right)} r^{2}\left[\frac{1}{r^{2}}+\frac{\lambda}{r}\right] \quad](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-514ad8afbf25cd57a0bc62f92316ce07_l3.png "Rendered by QuickLaTeX.com")
where 
and 
Estimate the change in the ground state energy of an H-atom if 
times the mass of an electron.
Auger electron emitted by Chromium by absorbing the energy from an 
to 
transition.
and 
. This is because the wavelength of transition depends to a certain extent on the nuclear mass. If nuclear motion is taken into account then the electrons and nucleus revolve around their common centre of mass. Such a system is equivalent to a single particle with a reduced mass 
, revolving around the nucleus at a distance equal to the electron-nucleus separation. Here 
where 
is the nuclear mass and 
is the electronic mass. Estimate the percentage difference in wavelength for the 1 st line of the Lyman series in 
, Mass of 
, Mass of electron 
kg.)
and 
. If instead of Hydrogen, we consider Deuterium, calculate the shift in the wavelength of these lines.
atom in ground state so that it can emit an Hy line in Balmer series? If the angular momentum of the system is conserved, what would be the angular momentum of such Hy photon?
th level from levels higher than 
are approximate harmonics (i.e. in the ratio 
) when 
.
be the energy of the nth level of H-atom. If all the H-atoms are in the ground state and radiation of frequency 
falls on it
state
state
molecule consists of two oxygen atoms. In the molecule, nuclear force between the nuclei of the two atoms
, according to the simple Bohr model. Angular momentum is a vector and hence there will be infinitely many orbits with the vector pointing in all possible directions. In actuality, this is not true,
electron mass 
If one decides to work in a frame of reference where the electron is at rest, the proton would be moving around it. By similar arguments, the binding energy would be 
(M = proton mass) This last expression is not correct because
, the radius of 
ion in its ground state, on the basis of Bohr’s model, will be about
and magic no. of neutrons 
and 
are found to be very stable
and 
. The proton separation energy for a nuclide is the minimum energy required to separate the least tightly bound proton from a nucleus of that nuclide. It is given by 
. Given 
, 
of an unknown radioactive nuclide is measured at hourly intervals. The results found are tabulated as follows: ![\[\begin{tabular}{|l|l|l|l|l|l|} \hline$t(\mathrm{~h})$ & 0 & 1 & 2 & 3 & 4 \\ \hline R(MBq) & 100 & $35.36$ & $12.51$ & $4.42$ & $1.56$ \\ \hline \end{tabular}\]](https://www.learnatnoon.com/s/wp-content/ql-cache/quicklatex.com-2cff4d33a1ea1a3274f405d5eee59de6_l3.png "Rendered by QuickLaTeX.com")
and calculate half-life from the graph.
versus 
and obtain the value of half-life from the graph.
. If this was true, show that if the neutron was at rest, the proton and electron would emerge with fixed energies and calculate them. Experimentally, the electron energy was found to have a large range.
and e bound by electrostatic forces. If we consider the force between neutron and proton in deuteron as given in the form of a Coulomb potential but with an effective charge 
estimate the value of 
given that the binding energy of a deuteron is 
.
. The number of 
is of count zero at 
. At what value of 
and 
?
.
activity of 12 disintegrations per minute per gram of its carbon content. The 
activity of the living wood is 16 disintegrations per minute per gram. How long ago did the tree, from which the wooden sample came, die? Given the half-life of 
through the following sequence: 
Here 
is an intermediate nuclei which is also radioactive. Considering that there are 
atoms of A initially, plot the graph showing the variation of number of atoms of 
and 
versus time.
and 
nuclei have the same mass number. Do they have the same binding energy?
and 
are the disintegration constants of A and B respectively. In which of the following cases, the two samples can simultaneously have the same decay rate at any time?
and 
. If one of the neutrons in Triton decays, it would transform into He3 nucleus. This does not happen. This is because
nucleus
and 
denote the atomic masses of the parent and the daughter nuclei respectively in a radioactive decay. The Q-value for a 
– decay is 
and that for a 
decay is 
. If me denotes the mass of an electron, then which of the following statements is correct?
and 
and 
and 
and 
, where r is in km and
melectron 
magnitude of the potential energy of electron in the 
over a surface, then a) the electric field inside the surface and on it is zero b) the electric field inside the surface is necessarily uniform c) the number of flux lines entering the surface must be equal to the number of flux lines leaving it d) all charges must necessarily be outside the surface
, and 
are fixed at their positions as shown in the figure. 
is a Gaussian surface. The Gauss’s law is given by 
Which of the following statements is correct? a) E on the LHS of the above equation will have a contribution from q1, q3, and q5 while q on the RHS will have a contribution from q2 and q4 only b) E on the LHS of the above equation will have a contribution from all charges while q on the RHS will have a contribution from q2 and q4 only c) E on the LHS of the above equation will have a contribution from all charges while q on the RHS will have a contribution from q1, q3, and q5 only d) both E on the LHS and q on the RHS will have contributions from q2 and q4 onlyv
and 
Show that
to prove 
, prove that 
over the rectangular loop 1234 shown in the figure
over the surface bounded by loop 1234
is placed symmetrically along the z-axis and has radius 
. The cable consists of a thin wire and a co-axial conducting tube. An alternating current 
sin 
flows down the central thin wire and returns along the co-axial conducting tube. The induced electric field at a distance 
from the wire inside the cable is 
. In 
, 
has permittivity 
, permeability 
and resistivity 
. Imagine a parallel plate capacitor immersed in seawater and driven by an alternating voltage source 
What fraction of the conduction current density is the displacement current density?
is placed along the z-axis. The wire is set into motion along its length with a uniform velocity 
Calculate the pointing vectors 
parallel plate capacitor. How would you establish an instantaneous displacement current of 
in the space between its plates?
is given by 
is used in satellite communication
is used to kill germs in water purifies
is used to detect leakage of oil in underground pipelines
is used to improve visibility in runaways during fog and mist conditions
. Show that nature of 
. What is the average intensity of the beam?
. The plates are very large and close together. Neglecting the edge effects, find the displacement current through the capacitor?
m square, 
m thickness) of sodium, which produces a photocurrent of 100µA when a light of intensity 100W/m2 (λ = 660nm) falls on it. Find the probability that a photoelectron is produced when a photon strikes a sodium atom. [Take density of Na = 0.97 kg/m3].
on it. Which of the following are true?
if the wave is totally absorbed
if the wave is totally reflected
if the wave is totally reflected
for real surface
. The electromagnetic waves produced:
(b)
(c) 
(d) 
nm (c) 
nm (d)
nm
and is in a magnetic field 
Then it’s de Broglie wavelength (a) remains constant (b) increases with time (c) decreases with time (d) increases and decreases periodically
-direction can have the following pairs of 
and 
-axis is given as: 
. Choose the correct options from the following a) the associated magnetic field is given as 
Choose the correct options from the following:
as the amplitude of its electric field vector. The electric field 
which transports significant energy from the source falls off as
bulb at a 
distance is E. The electric field intensity produced by the radiations coming from 
bulb at the same distance is
falls on a non-reflecting surface at normal incidence. If the surface has an area of 
, the total momentum delivered during 30 minutes is
is incident normally on a perfectly reflecting infinite wall at 
.
, the voltage source stops and R is short-circuited. Now write down how much energy is stored in each of L and C.
,
. Another device has twice the values for 
, 
and 
. How are the answers affected?