Recent questions tagged medium

The ratio of contribution made by the electric and magnetic field components to the intensity of an EM wave is

asked Aug 19, 2016 by meena.p

1 answer

A linearly polarized electromagnetic wave given as $E=E_0 \hat i \cos (kz-wt)$ is incident normally on a perfectly reflecting infinite wall at $z=a$ Assuming that the material of the wall is optically inactive , the reflected wave will be given as

asked Aug 19, 2016 by meena.p

1 answer

One requires $11\;ev$ of energy to dissociate a carbon monoxide molecule into carbon and oxygen atoms. The minimum frequency of the appropriate electromagnetic radiation to achieve dissociation lies in

asked Aug 18, 2016 by meena.p

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A radio can tune any station in the $7.5 \;MHz$ to $12\;MHz$ band . What is the corresponding wave length band ?

asked Aug 17, 2016 by meena.p

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A plane electro magnetic wave travels in vaccum along z- direction . What can you say about the direction of its electric and magnetic field vectors ? If the frequency of the wave is $30\;MHz$ What is its wave length ?

asked Aug 17, 2016 by meena.p

1 answer

A parallel plate capacitor made of circular plates each of radius $R=6.0\;cm$ has a capacitance $c= 100\;pF$. The capacitor is connected to a $230\;v$ a.c supply with an angular frequency of $300\;rad\;S^{-1}$ . What is the r.m.s value of the conduction current ?Determine the magnitude of Bata point 3.0 cm from the axis between the plates

asked Aug 16, 2016 by meena.p

1 answer

The figure shows a capacitor made of two circular plate each of radius 12 cm and separated and separated by 5.0 mm . The capacitor is being changed by an external source (not shown in the figure ). The changing current is constant and equal to $0.15\;A$ Calculate the capacitor and the rate of change of potential difference between the plates.obtain the displacement

asked Aug 16, 2016 by meena.p

1 answer

The figure shows a capacitor made of two circular plate each of radius 12 cm and separated and separated by 5.0 mm . The capacitor is being changed by an external source (not shown in the figure ). The changing current is constant and equal to $0.15\;A$ Calculate the capacitor and the rate of change of potential difference between the plates

asked Aug 16, 2016 by meena.p

1 answer

The binding energy of deuteron is $2.2 \;Mev$ and that of $_2He^4$ in $28\;Mev$ . If two deuterons are fused to form one $_2He^4$, then the energy released is

asked Aug 16, 2016 by meena.p

1 answer

A radioactive substance decays to $ \large\frac{1}{16}$ of its initial activity in 40 days . The half life of the radio active substance expressed in days is

asked Aug 16, 2016 by meena.p

1 answer

Consider the so called $D-T reaction$ (determination - tritium) calculate the energy released in Mev in this reaction from the data $m(_1H^2)=2.0141024 $ and $m(_1H^3) =3.0160494$

asked Aug 9, 2016 by meena.p

1 answer

Consider the so called D -T reaction (deuterium - tritium fusion ) $_1H^2 +_1H^{3} \to _2He^{4} +n$ consider the radius of both detriment and tritium to be approximately $2.0\;fm$ . What is the kinetic energy needed to overcome the coulomb repulsion between the two nuclei? To what temperature must the gases be heated to initiate the reaction ?

asked Aug 9, 2016 by meena.p

1 answer

Consider the fission of $_{92}U^{238}$ by fast neutrons. In one fission event , no neutron are emitted and the final stable end products , after the beta decay of the primary fragments are $_{58}Ce ^{140}$ and $_{44}Ru ^{99}$ . Calculate Q for this fission process . The relevant atomic and particle masses are :$m(_92U^{238})=238.05079\;u$$m(_{34} Ru^{99}) = 98.90594\;u$$m(_{58}Ce^{140})=139.90543\;u$

asked Aug 9, 2016 by meena.p

1 answer

Under certain circumstance , a nucleolus can decay by emitting a particle more massive than an $ \alpha$ particle . Consider the following : $_{88}Ra^{223} \to _{86} Rn ^{219} +_2 He ^{14}$ Calculate the Q value for this decay and determine if it energetically possible .

asked Aug 9, 2016 by meena.p

1 answer

Under certain circumstance , a nucleolus can decay by emitting a particle more massive than an $ \alpha$ particle . Consider the following : $_{88}Ra^{223} \to _{82} Pb ^{209} +_6C^{14}$ Calculate the Q value for this decay and determine if it energetically possible .

asked Aug 5, 2016 by meena.p

2 answers

A Source contains two phosphors radio nuclides $ _{15}P^{32}(T_{1/2}=14.3\;days)$ and $_{15}P^{33} (T_{1/2} =25.3\;day)$ Initially $10\%$ of the decays come from $_{15}P^{33}$. How long one must wait until $90\%$ do so ?

asked Aug 5, 2016 by meena.p

1 answer

The neutron separation energy is defined to be the energy required to remove a neutron from a nucleus. Obtain the neutron separation energy of the nuclei $_{20}Ca ^{41}$ from the following data : $m(_{20}Ca^{40})=39.962591\;u,m(_{20}Ca^{41})=40.962278\;u,m(_{13}Al^{27})=26.981514\;u$

asked Aug 5, 2016 by meena.p

1 answer

From the relation $R=R_0A^{1/3}$, where $R_0$ is a constant and A is the mass number of a nucleus , show that the nuclear matter density is nearly a constant (ie independent of A)

asked Aug 4, 2016 by meena.p

1 answer

Calculate the height of potential barrier for a head on collision of two denterons. The effective radius of deuteron can be taken to be $2 fm$ . Note that height of potential barrier is given by the coulmb repulsion between two denterons when they just touch each other .

asked Aug 3, 2016 by meena.p

1 answer

The fission properties of $_{84}Pu^{237}$ are similar to those of $_{92} U^{35}$ . The average energy released per fission is $180\;Mev$ How much energy in Mev is released if all the atoms in 1 kg of pure $_{94} Pu ^{239}$ undergo fission .

asked Aug 3, 2016 by meena.p

1 answer

Suppose we think of fission of a $_{26}Fe^{56}$ nucleus into two fragment $_{13} Al ^{26}$. Is the fission energetically possible ? Argue by working out Q of the process. cives.

asked Aug 3, 2016 by meena.p

1 answer

The Q value of a nuclear reaction $A+b=c+A$ is defined by $[m_A+m_b-m_c-m_d] C^2$ where masses refers to the respective nuclei. Determine from the given data the Q value of the following reaction and state whether the reaction are exothermic or endothermic . $_6C^{12}+_6C^{12} \to _{10}Ne^{20} +_2He^4$

asked Aug 2, 2016 by meena.p

1 answer

The Q value of a nuclear reaction $A+b=c+A$ is defined by $[m_A+m_b-m_c-m_d] C^2$ where masses refers to the respective nuclei. Determine from the given data the Q value of the following reaction and state whether the reaction are exothermic or endothermic .$_1H^1+_1H^3 \to _1H^2 +_1H^2$

asked Jul 22, 2016 by meena.p

1 answer

The nucleus $_{10} Ne ^{23}$ decays by $\beta ^{-}$ emission. write down the $\beta^{-}$ decay equation and determine the maximum kinetic energy of the electrons emitted from the following data. $ m (_{10} Ne ^{23} ) = 22.994466\;amu \;\qquad m (_{11} Na ^{23} ) = 22.989770\;amu $

asked Jul 22, 2016 by meena.p

1 answer

The radio nuclide $_6C^{11}$ decays according to $_6C^{11} \to _5B^{11}+e^++\gamma$ half life $=20.3\;min$ The maximum energy of the emitted position is $0.960\;Mev$ given the mass values $m(_6C^{11})=11.011434 \;u\;m (_6B^{11})=11.009305$ calculate Q and compare it with maximum energy of position emitted .

asked Jul 13, 2016 by meena.p

1 answer

Given $m(_{86} R_n ^{220} =220.1137\;u; m(_{84}Po^{216})=216.00189u$ and $m_{\alpha}=4.00260 \;u$ Find the Q value and K.E of the emitted $ \alpha$ particle in the $\alpha$ decay of $_{86} Rn ^{220}$

asked Jul 13, 2016 by meena.p

1 answer

Find the Q value and the kinetic energy of emitted $\alpha$ particle in the $\alpha$ decay of $_{88} Ra ^{226}$

asked Jul 13, 2016 by meena.p

1 answer

The half life of $_{38} Sr ^{90}$ is 28 years . What is the disintegration rate of $15\;mg$ of this isotope?

asked Jul 13, 2016 by meena.p

1 answer

Obtain the amount of $_{27}Co^{60}$ necessary to provide a radio active source 0f $8.0\;mci$ strength. Half life of $_{27} Co ^{60}$ is $5.3$ years

asked Jul 13, 2016 by meena.p

1 answer

The normal activity of living carbon containing matter is found to be about 15 decays /min for every gram of carbon . This activity arises from the small proportion of radioactive $_6C^{14}$ present with the ordinary $_6C^{12}$ isotope. When the organism is dead , its interaction with the atmosphere Which maintains the above equilibrium activity ,ceases and its activity begins to drop. From the known half life $(=5730 years) $ of $_6C^{14}$ and the measured activity , the age of the specimen can be approximately estimated the approximate age of the Indus valley civilization

asked Jul 12, 2016 by meena.p

1 answer

A radio active isotope has a half of T years. How long will it take the activity to reduce to $1\%$ of its original activity .

asked Jul 12, 2016 by meena.p

1 answer

A radio active isotope has a half of T years. How long will it take the activity to reduce to $3.125\%$

asked Jul 12, 2016 by meena.p

1 answer

An energy of $24.6\;ev$ is required to remove one of the electrons in (ev) is required to remove both the electrons from a neutral helium atom is

asked Jul 8, 2016 by meena.p

1 answer

When is $H_{\alpha}$ line of the Balmer series in the emission spectrum of hydrogen atom obtained ?

asked Jul 8, 2016 by meena.p

1 answer

The mass of a H- atom is less than the sum of the mass of a proton and electron , why is this ?

asked Jul 8, 2016 by meena.p

1 answer

The simple Bohr model is not applicable to $_2He^4$ atom because

asked Jul 8, 2016 by meena.p

1 answer

Let $E_n=\large\frac{-1me^4}{8\in_0^2 n^2h^2}$ be the energy of the nth level of H- atom . If all the H- atoms are in the ground state and radiation of frequency $(E_2-E_1) /h$ falls on it ,

asked Jul 8, 2016 by meena.p

1 answer

Consider aiming a beam of free electron towards free protons. when they scatter , an electron and a proton cannot combine to produce a H-atom .

asked Jul 8, 2016 by meena.p

1 answer

An ionized H- molecules consists of an electron and two protons. The proton are separated by a small distance of the order of any strom .In the ground state ,

asked Jul 7, 2016 by meena.p

1 answer

Two H atoms in the ground state collide inelastically . The maximum amount by which their combined kinetic energy is reduced is

asked Jul 7, 2016 by meena.p

1 answer

$O_2$ molecules consists of two oxygen atoms. In the molecule , nuclear force between the nuclei of the two atoms

asked Jul 7, 2016 by meena.p

1 answer

For the ground state, the electron in th H- atom has an angular momentum = h , 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 direction . In actuality this is not true.

asked Jul 7, 2016 by meena.p

1 answer

The binding energy of a H-atom , considering an electron moving around a fixed nuclei is $B= \large\frac{-me^4}{8n^2\in_0 h^2}$If one decides to work in a frame of reference where the electron is at rest , the proton would be around it. By similar arguments, the binding energy would be , $B=\large\frac{-Me^4}{8n^2\in_0^2h^2}$ This last expression is not correct because ,

asked Jul 6, 2016 by meena.p

1 answer

A hydrogen atom initially in the ground level absorbs a photon, which excites it to $n=4$ level. Determine the wave length and frequency of photon .

asked Jul 6, 2016 by meena.p

1 answer

What is the shortest wave length present in the paschen series of spectral lines ?

asked Jul 5, 2016 by meena.p

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Red light , how ever bright it is , cannot produce the emission of electrons from a clean zinc surface , But even weak ultra violet radiation can do so why ?

asked Jul 5, 2016 by meena.p

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The potential difference that much be applied to stop the fastest photo electron emitted by a nickel surface having work function $5.01\;ev$ When ultra violet light 0f 200 nm falls on it , must be

asked Jul 5, 2016 by meena.p

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The threshold wave length ,for photo electric emission from a material is $5200 A^{\circ}$ photo electron will be emitted when this material is illuminated with monochromatic radiation from a

asked Jul 5, 2016 by meena.p

1 answer

Find the de-Broglie wave length associated with an electron moving with velocity $0.6 \;C$ given , rest mass of electron $= 9.1 \times 10^{-31} \;kg$

asked Jul 4, 2016 by meena.p

1 answer

A photon and an electron both have energy of 100 ev . Which has greater wave length ?

asked Jul 4, 2016 by meena.p

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