Recent questions tagged ncert

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

The number of photons entering the pupil of our eye per second corresponding to the minimum intensity of white light that we humans can perceive . Take the area of the pupil to be about $0.4\;cm^2$ and the average frequency of white light to be found $6 \times 10^4 Hz$

asked Jun 27, 2016 by meena.p

1 answer

Estimate the number of photons emitted per second by a Mw transmitter of 10 Kw power emitting radio waves of length 500 m

asked Jun 27, 2016 by meena.p

1 answer

In an acceleration experiment on high energy collision of electrons with position , a certain event is interpreted as annihilation of an electron position pair of total energy $10.2\;Bev$ into two $\gamma$ rays of equal energy. What is the wave length associated with each $\gamma$- ray $(1Bev= 10^9\;ev)$ ?

asked Jun 27, 2016 by meena.p

1 answer

An x-ray tube produces a continuous spectrum of radiation with its short wave length end at $0.45 A^{\circ}$ give what order of accelerating voltage (for electron ) is required in such a tube .

asked Jun 27, 2016 by meena.p

1 answer

An x-ray tube produces a continuous spectrum of radiation with its short wave length end at $0.45 A^{\circ}$ what is the maximum energy of a photon in the radiation ?

asked Jun 27, 2016 by meena.p

1 answer

An electron gun with its anode at a potential $100\;v$ fires out electrons in a spherical bulls containing hydrogen gas at low pressure $(10^{-2}\;mm\;of\;Hg)$ . A magnetic field of $2.83 \times 10^{-4}\;T$ curves the path of the electron in a circular orbit of radius 12.0 cm (The path can be viewed because the gas ions in the path focus the beam by attracting electrons and emitting light by electron capture. this method is known as "fine beam tube " method. Determine e/m from the data .

asked Jun 24, 2016 by meena.p

1 answer

A mono energetic electron beam with electron speed of $5.20 \times 10^6 ms^{-1}$ is subjected to a mognetic field of $1.30 \times 10^{-4}\;T$ , normal to the beam velocity .What is the radius of the circle traced by the beam , given $\large\frac{e}{m}$ for electron equals $1.76 \times 10^{11} ckg^{-1}$Is the formula you employ valid for calculating radius of the path of 20 Mev electron beam ? If not in what way is it modified ?

asked Jun 24, 2016 by meena.p

1 answer

A mono energetic electron beam with electron speed of $5.20 \times 10^6 ms^{-1}$ is subjected to a mognetic field of $1.30 \times 10^{-4}\;T$ , normal to the beam velocity .What is the radius of the circle traced by the beam , given $\large\frac{e}{m}$ for electron equals $1.76 \times 10^{11} ckg^{-1}$

asked Jun 24, 2016 by meena.p

1 answer

Estimate the speed with which electron emitted from a heated cathode of an evacuated tube impinge on the anode maintained at a potential difference of $500\;v$ , with respect to the cathod . Ignore the small initial speeds of the electrons . The specific charge of the electron (ie) its $\large\frac{e}{m}$ is given to be $1.76 \times 10^{11}\;kg^{-1}$ use the same formula you employ to obtain electron speed for an anode potential of 10 Mv. Do you see what is wrong ? In what way in is the formula to be modified ?

asked Jun 24, 2016 by meena.p

1 answer

Estimate the speed with which electron emitted from a heated cathode of an evacuated tube impinge on the anode maintained at a potential difference of $500\;v$ , with respect to the cathode . Ignore the small initial speeds of the electrons . The specific charge of the electron (ie) its $\large\frac{e}{m}$ is given to be $1.76 \times 10^{11}\;kg^{-1}$

asked Jun 24, 2016 by meena.p

1 answer

What is the de-Broglie wavelength of a nitrogen molecule in air at $300\;K$ Assume that the molecule that the molecule is moving with the root- means - square speed of molecules at this temperature ? (Atomic mass of nitrogen = $14.0076\;u$) given : $h= 6.63 \times 10^{-34}\;Js,m_n= 1.675 \times 10^{-27}\;kg; k= 1.8 \times 10^{-23}JK^{-1}$

asked Jun 24, 2016 by meena.p

1 answer

Show that the wave length of electro magnetic radiation is equal to the de-Broglie wave length of its quantum (photon)

asked Jun 23, 2016 by meena.p

1 answer

Find the de-Broglie wavelength of a neutron , in thermal equilibrium with matter, having an average kinetic energy of $ \large\frac{3}{2}$$kT$ at $300k$ .given : $h= 6.63 \times 10^{-34}\;Js,m_n= 1.675 \times 10^{-27}\;kg; k= 1.8 \times 10^{-23}JK^{-1}$

asked Jun 23, 2016 by meena.p

1 answer

For what kinetic energy of a neutron will the associated de-Broglie wave length be $1.40 \times 10^{-10}\;m$ given : $h= 6.63 \times 10^{-34}\;Js,m_n= 1.675 \times 10^{-27}\;kg; k= 1.8 \times 10^{-23}JK^{-1}$

asked Jun 23, 2016 by meena.p

1 answer

An electron and a photon each have a wave length of $1.00\;nm$ calculate the kinetic energy of the electron .given $h= 6.63 \times 10^{-34}\;Js,m_e= 9 \times 10^{-31}\;kg$

asked Jun 23, 2016 by meena.p

1 answer

An electron and a photon each have a wave length of $1.00\;nm$ calculate the energy of the photon. $h= 6.6 \times 10^{-34}\;Js,m_e= 9 \times 10^{-31}\;kg$

asked Jun 23, 2016 by meena.p

1 answer

An electron and a photon each have a wave length of $1.0\;nm$ . Find their momentum. $(h= 6.6 \times 10^{-34}\;Js)$

asked Jun 23, 2016 by meena.p

1 answer

What is the de-Breglie wave length of a dust particle of mass $1.0 \times 10^{-9}\;kg$ drifting with a speed of $2.2ms^{-1}$? $(h= 6.6 \times 10^{-34}\;Js)$

asked Jun 23, 2016 by meena.p

1 answer

What is the de-Broglie wave length of a ball of mass $0.060\;kg$ moving at a speed of $1.0ms^{-1} $?

asked Jun 23, 2016 by meena.p

1 answer

What is the de-Broglie wave length of a bullet of mass $0.040\;kg$ travelling at the speed of $1.0kms^{-1}$? $h= 6.63 \times 10^{-34}\;Js$

asked Jun 23, 2016 by meena.p

1 answer

The wave length of light from the spectral emission line of sodium is $589\;nm$ . Find the kinetic energy at which a neutrals would have the same de - Broglie wavelength . given $(h= 6.6 \times 10^{-34}\;Js, mn=1.66 \times 10^{-27}\;kg)$

asked Jun 23, 2016 by meena.p

1 answer

The wave length of light from the spectral emission line of sodium is $589\;nm$ . Find the kinetic energy at which an electron would have the same de- Brojlie wavelength . given $(h= 6.6 \times 10^{-34}\;Js, me= 9 \times 10^{-31}kg, \; m_n =1.66 \times 10^{27}\;kg)$

asked Jun 23, 2016 by meena.p

1 answer

What is the de- Broglie wave length of an electron with kinetic energy of $120 ev$ given $(h= 6.63 \times 10^{-34}\;Js, me= 9 \times 10^{-31}kg, \; lev =1.6 \times 10^{-19}\;J)$

asked Jun 23, 2016 by meena.p

1 answer

What is the speed of an electron with kinetic energy of $120\;eV$ given $h= 6.63 \times 10^{-34} \;Js, \;m_e= 9 \times 10^{-31} kg,lev= 1.6 \times 10^{-19}\;J$

asked Jun 23, 2016 by meena.p

1 answer

What is the momentum of an electron with kinetic energy of $120\; ev$ given $(h= 6.63 \times 10^{-34}\;Js, lev =1.6 \times 10^{-19}\;J)$

asked Jun 23, 2016 by meena.p

1 answer

Calculate the momentum and de-Broglie wave length of the electrons acceleration through a potential difference of $56\; v.$

asked Jun 23, 2016 by meena.p

1 answer

Light of wave length 488 nm is produced by an argon laser which is used in the photo electric effect . When light from this spectral line is incident on the cathode , the stopping potential of photo electrons is $0.30\;ev$ . Find the work function of the material from which the cathode is made. given $(h= 6.63 \times 10^{-34}\;Js, lev =1.6 \times 10^{-19}\;J)$

asked Jun 23, 2016 by meena.p

1 answer

Light of wave length 488 nm is produced by an argon laser which is used in the photo electric effect . When light from this spectral line is incident on the cathode , the stopping potential of photo electrons is $0.30\;ev$ . Find the work function of the material from which the cathode is made.given $(h= 6.63 \times 10^{-34}\;Js, me= 9 \times 10^{-31}kg, \; lev =1.6 \times 10^{-19}\;J)$

asked Jun 23, 2016 by meena.p

1 answer

Light of frequency $7.21 \times 10^{14} Hz$ is incident on a metal surface . Electron with a maximum speed of $6.0 \times 10^5\;ms^{-1}$ are ejected from the surface. What is the threshold frequency for photo emission of electron ? $ h =6.63 \times 10^{-34}Js, m_e=9.1 \times 10^{-31} \;kg$

asked Jun 22, 2016 by meena.p

1 answer

The work function for a certain metal is $4.2\;ev$ will this metal give photo electric emission for incident radiation of wave length $330 nm? $

asked Jun 22, 2016 by meena.p

1 answer

The threshold frequency of a certain metal is $3.3 \times 10^{14}\;Hz$ . If light of frequency $8.2 \times 10^{14}\;Hz$ is incident on the metal, Predict the cut off voltage for photo electric emission . Given Planck's Constant , $h= 6.62 \times 10^{-34} \;Js$

asked Jun 22, 2016 by meena.p

1 answer

A 100 w sodium lamp radiates energy uniformly in all directions. The lamp is located at the center of a large sphere that absorbs all the sodium light which is incident on it. The wavelength of the sodium light is $589\;nm$ At what rate are the photons delivered to the sphere ?

asked Jun 22, 2016 by meena.p

1 answer

A 100 w sodium lamp radiates energy uniformly in all directions. The lamp is located at the center of a large sphere that absorbs all the sodium light which is incident on it. The wavelength of the sodium light is $589\;nm$ what is the energy associated per photon with the sodium light ?

asked Jun 22, 2016 by meena.p

1 answer

Is an experiment on photo effect, the slope of the cut off voltage versus frequency of incident light is found to be $4.12 \times 10^{-15} Vs $ given $e= 1.6 \times 10^{-19}\;c$ estimate the value of planes constant

asked Jun 21, 2016 by meena.p

1 answer

The energy flux of sun light reaching the surface of the earth is $1.388 \times 10^3 w/m^2$. How many photons (nearly) per sq.m are incident on the earth per sec ? Assume that the photons in the sunlight have an average wave length of $550 \;nm$

asked Jun 21, 2016 by meena.p

1 answer

Monochromatic light of wave length $632.8\;nm$ is produced by a helium - neon laser. The power emitted is $9.42\;mw$. How fast does a hydrogen atom have to travel in order to have the same momentum as that of the photon .

asked Jun 21, 2016 by meena.p

1 answer

Monochromatic light of wave length $632.8\;nm$ is produced by a helium - neon laser. The power emitted is $9.42\;mw$. How many photons per energy, on the average, arrive at a target irradiated by this beam ? (Assume the beam to have uniform cross - section which is less than the target area )

asked Jun 21, 2016 by meena.p

1 answer

Monochromatic light of wave length $632.8\;nm$ is produced by a helium - neon laser. The power emitted is $9.42\;mw$. Find the energy and momentum of each photon in the light beam

asked Jun 21, 2016 by meena.p

1 answer

The photoelectric cut off voltage in a certain experiment is $1.5 \;v$ What is the maximum kinetic energy of photo electron emitted ?

asked Jun 21, 2016 by meena.p

1 answer

The work function of caesium metal is $2.14$ ev when light of frequency $6 \times 10^4 \;Hz$ is incident on the metal surface , photo emission of electron occur. what is the a) maximum speed of the emitted photo electrons

asked Jun 21, 2016 by meena.p

1 answer

The work function of caesium metal is $2.14$ ev when light of frequency $6 \times 10^4 \;Hz$ is incident on the metal surface , photo emission of electron occur. what is the stopping potential

asked Jun 21, 2016 by meena.p

1 answer

The work function of caesium metal is $2.14$ ev when light of frequency $6 \times 10^4 \;Hz$ is incident on the metal surface , photo emission of electron occur. what is the a) maximum kinetic energy of emitted electrons

asked Jun 21, 2016 by meena.p

1 answer

Find the minimum wave length of x - rays produced by $30\; kv$ electron . given $h= 6.63 \times 10^{-34}\;Js$

asked Jun 21, 2016 by meena.p

1 answer

Find the maximum frequency of x- rays produced by $30\; kv$ electrons. Given, $h= 6.63 \times 10^{-34}\;Js$

asked Jun 21, 2016 by meena.p

1 answer

Consider a light beam incident from air to a glass slab at Brewster's angle as shown. A Polaroid is placed of the emergent ray at a point P and rotated about an axis passing through the center and perpendicular to the plane of the polaroid .

asked Jun 15, 2016 by meena.p

1 answer

Ask Questions, Get Answers