Recent questions tagged ch11

If the kinetic of a particle is increased by 16 times , the percentage change in the de - Broglie wave length of the particle is

asked Jul 5, 2016 by meena.p

1 answer

What is the energy of a photon whose wave length is $6840 ^{\circ}A$

asked Jul 5, 2016 by meena.p

1 answer

A proton and an $\alpha$ particle are accelerated through a potential difference of $100\;v$ . The ratio of the wave length associated with the proton to that associated with an $\alpha$ particle is

asked Jul 5, 2016 by meena.p

1 answer

If the kinetic energy of a free electron doubles , its de-Broglie wave length charges by a factor ,

asked Jul 5, 2016 by meena.p

1 answer

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

The maximum Kinetic energy of photo electron emitted from a surface when photons of energy $6ev$ fall on it is $4ev$. the stopping potential in volt is

asked Jul 5, 2016 by meena.p

1 answer

What is the momentum of a photon from ultra violet light of wave length $ \lambda= 332 \;nm$

asked Jul 4, 2016 by meena.p

1 answer

Find the ratio of de-Broglie wave lengths associated with two electrons beams , accelerated through $25V$ and $36V$ respectively

asked Jul 4, 2016 by meena.p

1 answer

What is the value of stopping potential between the cathode and the anode of a photocell , if the maximum kinetic energy of the electron emitted is $5ev$

asked Jul 4, 2016 by meena.p

1 answer

What is the energy of a photon in ev corresponding to the visible light of maximum wave length ?

asked Jul 4, 2016 by meena.p

1 answer

What is the momentum of photon of energy 3 Mev in $kgms^{-1}$?

asked Jul 4, 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

1 answer

A neutron beam of energy E scatters from atoms on a surface with a spacing $d= 0.1 nm$ . The first maximum of initially in the reflected beam occurs at $ \theta= 30^{\circ}$ . What is the kinetic energy E of the beam in eV?

asked Jul 4, 2016 by meena.p

1 answer

Two monochromatic beams A and B of equal intensity I , hit a screen . The number of photons hitting the screen by beam A is twice that by beam B. Then What inference can you make about their frequencies ?

asked Jul 4, 2016 by meena.p

0 answers

There are two sources of light each emitting with a power of 100 w. one emits X- rays of wave length 1 nm and the other visible light at 500 nm. Find the radio of no of photons of x- rays to the photons of visible light of the given wave length ?

asked Jul 4, 2016 by meena.p

1 answer

Do all the electrons that absorb a photon come out as photo electrons ?

asked Jul 4, 2016 by meena.p

1 answer

In the explanation of photo electric effect , we assume one photon of frequency $\alpha$ collide with an electron and transfer its energy . This leads to the equation for the maximum energy $E_{max}$ of the emitted electron as $ E_{max}= h \alpha - \phi _0$ where $ \phi _0$ is the work function of the metal. If an electron absorbs 2 photons (each of frequency ) what will be the maximum energy for the emitted electron ?

asked Jul 4, 2016 by meena.p

1 answer

A proton and an $\alpha $ particle are accelerated , using the same potential difference . How are the de- Broglie wave length $ \lambda_p$ and $\lambda_{\alpha}$ related to each other ?

asked Jul 4, 2016 by meena.p

1 answer

A particle moves in a closed orbit around the orgin . The de- Broglie wave length of the particle varies cyclically between two values $ \lambda_1 , \lambda_2$ with $ \lambda_1 > \lambda_2$ Which of the following statements are true ?

asked Jul 4, 2016 by meena.p

1 answer

Photons absorbed in matter are converted to heat , A source emitting n photons/ sec of frequency $\gamma$ is used to convert $1 kg$ of ice at $ 0^{\circ}C$ to water at $ 0^{\circ}C$ . Then , the time taken for the conversion .

asked Jul 4, 2016 by meena.p

1 answer

The de- Broglie wave length of a photon is twice the de- Broglie wave length of an electron. The speed of the electron is $v_e = \large\frac{c}{100}$ . Then

asked Jul 4, 2016 by meena.p

1 answer

Two particles $A_1$ and $A_2$ of masses $m_1$ and $m_2 (m_1 > m_2)$ have the same de -broglie wave length then

asked Jul 4, 2016 by meena.p

1 answer

Relativistic correction become necessary when the expression for the kinetic energy $\large\frac{1}{2}$$mv^2$ becomes comparable with $mc^2$ where m is the mass of the particle . At what de- broglie wave length will relativistic correction become important for an electron ?

asked Jul 4, 2016 by meena.p

1 answer

An electron (mass m) with an initial velocity $ \overrightarrow{v} =v_0 \hat i$ is in an electric field $ \overrightarrow{E} = E_0 \hat j$. If $\lambda_0 = \large\frac{h}{mv_0}$ , Its de-Broglie wave length at time t is given by

asked Jul 4, 2016 by meena.p

1 answer

An electron (mass m) with an initial velocity $ \overrightarrow{v} =v_0 \hat i (v_0 > 0) $ is in an electric field $ \overrightarrow{E} =- E_0 \hat i (E_0= constant >0) $ . Its de-Broglie wave length at time t is given by

asked Jul 4, 2016 by meena.p

1 answer

An electron is moving with an initial velocity $\overrightarrow{v} =v_0 \hat i $ and is in a magnetic field $\overrightarrow{B}= B_o \hat j$ Then its de -Broglie wave length

asked Jul 4, 2016 by meena.p

1 answer

A Proton , a neutron , an electron and an $\alpha$ particle have same energy.Then their de Broglie wave length compare as :

asked Jul 4, 2016 by meena.p

1 answer

Consider beam of electron (each electron with energy $E_0$ ) incident on a metal surface kept in an evaluated chamber. Then

asked Jun 30, 2016 by meena.p

1 answer

The wave length of a photon needed to remove a proton from a nucleus which is bound to the nucleas with 1 Mev energy is nearly

asked Jun 30, 2016 by meena.p

1 answer

A particle is dropped from a height H. The de-Broglie wave length of the particle as a function of height is proportional to

asked Jun 30, 2016 by meena.p

1 answer

The energy and momentum of an electron are related to the frequency and wave length of the associated matter wave by the relation $E= h \gamma,P=\large\frac{h}{\lambda}$ But while the value of $\lambda $ is physically significant the value of $\gamma$ (and therefore the value of phone speed ) has no physical significance why ?

asked Jun 30, 2016 by meena.p

1 answer

Every metal has a definite work function. Why do all photo electrons not come out with the same energy if incident radiation is monochromatic ? why there an energy distribution of photo electron ?

asked Jun 30, 2016 by meena.p

1 answer

Why should gases be insulators at ordinary pressures, and start conducting at low pressures.

asked Jun 30, 2016 by meena.p

1 answer

What is so special about the combination e/m ? Why do we not simply talk of e and m separately ?

asked Jun 29, 2016 by meena.p

1 answer

Quarks inside protons and neutrons are through to carry factional charges $\bigg[+\bigg( \large\frac{2}{3}\bigg):\bigg( \large\frac{-1}{3}e\bigg)\bigg]$ why do they not show up in Millikan's oil-drop experiment ?

asked Jun 29, 2016 by meena.p

1 answer

Compute the typical de-Broglie wave length of an electron in a metal at $27^{\circ}$ C and compare it with the mean separation between two electron in a metal which given to be about $2 \times 10^{-10}\;m$

asked Jun 29, 2016 by meena.p

1 answer

Find the typical de- Broglie wave length associated with a Helium gas at room temperature $(27^{\circ})$ and latm pressure, and compare it with the mean separation between two atoms under there conditions .

asked Jun 29, 2016 by meena.p

1 answer

The wave length of an probe is volubly a measure of the size of a structure that it can probe in some detail. The quark structure of protons and neutrons appear at the last minute length - scale of $10^{-5}\;m$ or less. This structure was first probed in early 1970's using high energy electron beam produced by a linear acceleration at stanford USA. guess what might have been the order of energy of these electron beams . (Rest mass energy of electron $=0.511\; Mev$)

asked Jun 29, 2016 by meena.p

1 answer

An election micro scope uses electrons accelerated by a voltage of 50 kv. Determined the de-Broglie wave length associated with the electrons. If other factor (such as numerical aperture ) are taken to be roughly the same, how does the resolving power of an electron microscope that uses yellow light ?

asked Jun 28, 2016 by meena.p

1 answer

Obtain the de-Broglie wave length associated with thermal neutrons at room temperature $27^{\circ}$ Hence explain why a fast neutron beam needs to be thermalised with the environment before it can be used for neutron diffraction experiments.

asked Jun 28, 2016 by meena.p

1 answer

Obtain the de- Broglies wave length of a neutron of kinetic energy $150\;ev$ would a neutron beam of same energy be equally suitable for crystal diffraction experiments ? Explain given $m_n= 1.6 \pi \times 10^{-27}\;kg$

asked Jun 28, 2016 by meena.p

1 answer

Crystal diffraction experiment can be performed using x- rays or electron acceleration through appropriate voltage ? Which probe has grater energy ? An x -ray photon or the electron ?

asked Jun 28, 2016 by meena.p

1 answer

Light of intensity $10^{-5} \;wm^{-2} $ falls on a sodium photocell of surface area $2 cm^2$ Assuming that the top 5 layers of sodium absorb the incident energy, estimate the time required for photo electric emission in the wave picture of radiation . The work function of the metal is given to be about 2 ev . What is the implication of your answer ? Effective atomic area $=10^{-20} m^2$

asked Jun 28, 2016 by meena.p

1 answer

The work function for the following metals is given $Ni: 5.15 \; ev$ What happen if the laser is brought never and placed 50 cm away ?

asked Jun 28, 2016 by meena.p

1 answer

The work function for the following metals is given $Na: 2.75 \; ev,k=2.30 \;ev ,Mo:4.17\;ev,Ni:5.15\;ev$ which of these metal will not give photo electric emission for a radiation of wave length , $3300 A^{\circ}$ from a He - cd laser placed 1 m away from the photo cell ?

asked Jun 28, 2016 by meena.p

1 answer

A mercury lamp is a convenient source for studying frequency dependence of photo electric emission , Since it gives a number of spectral lines rating from the uv to the red end of the visible spectrum . In our experiment with rubidium photo- cell , the following lines from a mercury source where used . $ \lambda_1 = 3650 A^{\circ}, \lambda_2 = 4047 A^{\circ}, \lambda_1 = 4358 A^{\circ}, \lambda_4 = 5461 A^{\circ}, \lambda_5 = 6907 A^{\circ}$The stopping voltages respectively were measured to be : $V_{o1}= 1.28 \;v , V_{o2}= 0.95 \;v, V_{o3}= 0.74 \;v, V_{o4}= 0.16\;v, V_{o5}= 1.28 \;v$ Estimate the threshold frequency and work function for the material .

asked Jun 27, 2016 by meena.p

1 answer

A mercury lamp is a convenient source for studying frequency dependence of photo electric emission , Since it gives a number of spectral lines rating from the uv to the red end of the visible spectrum . In our experiment with rubidium photo- cell , the following lines from a mercury source where used . $ \lambda_1 = 3650 A^{\circ}, \lambda_2 = 4047 A^{\circ}, \lambda_1 = 4358 A^{\circ}, \lambda_4 = 5461 A^{\circ}, \lambda_5 = 6907 A^{\circ}$The stopping voltages respectively were measured to be : $V_{o1}= 1.28 \;v , V_{o2}= 0.95 \;v, V_{o3}= 0.74 \;v, V_{o4}= 0.16\;v, V_{o5}= 1.28 \;v$ Determine the value of plark's constant be

asked Jun 27, 2016 by meena.p

1 answer

Monochromatic radiation of wave length $640.2 nm$ from a neon lamp irradiates a photo sensitive material made of calcium or tungsten. The stopping voltage is mentioned to be $0.54\;v$ . The source is replaced by an iron source and its $427.2\;nm$ line irradiates the same photo cell . predict the new stopping voltage .

asked Jun 27, 2016 by meena.p

1 answer

ultra violet light of wave length $2271A^{\circ}$ from a 100 w mercury source irradiates a photocell made of molybdenum metal. If the stopping potential is $13.v$ estimate the work function of the metal. How would the photo cell respond to a high intensity $(10^5wm^{-2})$ red light of wave length $6328\;A^{\circ}$ produced by $He- Ne$ laser ?

asked Jun 27, 2016 by meena.p

1 answer

Ask Questions, Get Answers