Recent questions tagged medium

Integrate : $\int \sqrt {\tan \theta} . d \theta $

asked Dec 30, 2013 by meena.p

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The shortest distance between the lines $\large\frac{x-6}{1}=\frac{2-y}{2}=\frac{z-2}{2}$ and $\large\frac{x+4}{3}=\frac{y}{-2}=\frac{1-z}{2}$ is?

asked Dec 29, 2013 by rvidyagovindarajan_1

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The equation of the plane passing through the point $(3,2,0) $ and the line $\large\frac{x-3}{1}=\frac{y-6}{5}=\frac{z-4}{4}$ is ?

asked Dec 28, 2013 by rvidyagovindarajan_1

1 answer

In a photocell experiment, a convex lens is used to focus the light beam. Current strength is I. If the lens is replaced by another lens of half diameter, but same focal length, photoelectric current will be

asked Dec 28, 2013 by thanvigandhi_1

1 answer

Maximum velocity of the photoelectrons emitted by a metal surface is $1.2 \times 10^6 m/s$. Assuming the specific charge of the electron to be $1.8 \times 10^{11}C/kg$, the value of the stopping potential is

asked Dec 28, 2013 by thanvigandhi_1

1 answer

When light of wavelength 300 nm falls on a photoelectric emitter, photoelectrons are liberated. For another emitter, light of wavelength 600 nm is sufficient for liberating photoelectrons. The ratio of the work function of the two emitters is

asked Dec 28, 2013 by thanvigandhi_1

1 answer

When photons of energy hv fall on an aluminum plate (of work function $E_{\circ}$) photoelectrons of maximum $KE,\: K$ are ejected. If the frequency of the radiation is doubled, the maximum kinetic energy of the ejected photoelectrons will be

asked Dec 28, 2013 by thanvigandhi_1

1 answer

A photocell employs photoelectric effect to convert

asked Dec 28, 2013 by thanvigandhi_1

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In photoelectric effect, the number of electrons ejected per second is

asked Dec 28, 2013 by thanvigandhi_1

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Relation of the stopping potential $V_{\circ}$ of a metal and the maximum velocity $v$ of the photoelectrons

asked Dec 28, 2013 by thanvigandhi_1

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Graph of $KE_{max}$ of the photoelectrons against v the frequency of the radiation incident on the metal is a straight line of slope equal to: , i

asked Dec 28, 2013 by thanvigandhi_1

1 answer

If in a photoelectric experiment, the wavelength of incident radiation is reduced from $6000\: A^{\circ} \: to \: 4000\: A^{\circ}$ , then

asked Dec 28, 2013 by thanvigandhi_1

1 answer

If the KE of a free electron doubles, its de-Broglie wavelength changes by the factor

asked Dec 28, 2013 by thanvigandhi_1

1 answer

A line makes angle $\theta$ with $x\:\:and\:\:z\:\:axis.$ If it makes angle $\beta$ with $y\; axis$, where $sin^2 \beta=3sin^2\theta$, then $ cos^2\theta=?$

asked Dec 28, 2013 by rvidyagovindarajan_1

1 answer

An electron is accelerated through a potential difference of V volt. It has a wavelength $ \lambda$ associated with it. Through what potential difference must an electron be accelerated so that its de-Broglie wavelength is the same as that of a proton? Take mass of a proton to be 1837 times larger than the mass of electron.

asked Dec 27, 2013 by thanvigandhi_1

1 answer

When the momentum of a proton is changed by an amount $p_{\circ}$, the corresponding change in de- Broglie wavelength is found to be $0.25 \%$. Then, the original momentum of the proton was

asked Dec 27, 2013 by thanvigandhi_1

1 answer

What is the effect of increasing the intensity of light that falls on the emitter in a photoelectric effect apparatus?

asked Dec 27, 2013 by thanvigandhi_1

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Mark the correct one

asked Dec 27, 2013 by thanvigandhi_1

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Which statement is incorrect regarding photoelectric effect?

asked Dec 27, 2013 by thanvigandhi_1

1 answer

The graph between stopping potential vs frequency is given for two different metals, then choose most appropriate statement

asked Dec 27, 2013 by thanvigandhi_1

1 answer

The line through the points $(5,1,a)\:\:and\:\:(3,b,1)$ crosses $yz$ plane at the point $(0,\large\frac{17}{2},-\frac{13}{2})$, then $(a,b)=?$

asked Dec 27, 2013 by rvidyagovindarajan_1

1 answer

If $P(3,2,6)$ is a point and $Q$ is a point on the line $\overrightarrow r=(\hat i-\hat j+2\hat k)+\lambda(-3\hat i+\hat j+5\hat k),$ then the value of $\lambda$ for which $\overrightarrow {PQ}$ is parallel to the plane $x-4y+3z=1$ is ?

asked Dec 27, 2013 by rvidyagovindarajan_1

1 answer

Two identical photo cathodes receive light of frequencies $f_1\: and \: f_2$. If velocities of photoelectrons (of mass m) coming out are respectively $v_1\: and\: v_2$, then

asked Dec 27, 2013 by thanvigandhi_1

1 answer

According to Einstein’s photoelectric equation, the plot of the KE of the emitted photoelectrons from a metal vs the frequency of the incident radiation gives a straight line whose slope

asked Dec 27, 2013 by thanvigandhi_1

1 answer

The length of the perpendicular drawn from the point $(3,-1,11) $ on the line $\large\frac{x}{2}=\frac{y-2}{3}=\frac{z-3}{4}$ is?

asked Dec 27, 2013 by rvidyagovindarajan_1

1 answer

If the KE of a free electron doubles, its de Broglie wavelength changes by a factor:

asked Dec 27, 2013 by thanvigandhi_1

1 answer

An electron is 2000 times lighter than a proton. Both are moving such that their matter waves have a length of $ 1\: \dot {A}$. The ratio of their kinetic energy in approximation is

asked Dec 27, 2013 by thanvigandhi_1

1 answer

The work function of a substance is $4.0\: eV$. The longest wavelength of light that can cause photoelectron emission from this substance is approximately

asked Dec 27, 2013 by thanvigandhi_1

1 answer

A proton, a deuteron and an alpha particle are accelerated through potentials of $V,\: 2V\: and\: 4V$ respectively. Their velocities will bear a ratio

asked Dec 27, 2013 by thanvigandhi_1

1 answer

A photoelectric cell is illuminated by a small bright source of light placed at 1m. If the same source of light is placed 2m away, the electrons emitted by the cathode

asked Dec 27, 2013 by thanvigandhi_1

1 answer

Light of wavelength $0.6\: \mu m$ from a sodium lamp falls on a photocell and causes the emission of photoelectrons for which the stopping potential is $0.5\: V$ and with light of wavelength $0.4\: \mu m$ from a sodium lamp, the stopping potential is $1.5\: V$. With this data, the value of $ \large\frac{h}{e}$ will be

asked Dec 27, 2013 by thanvigandhi_1

1 answer

When a light of wavelength $300\: nm$ falls on a photoelectric emitter, the photoelectrons are liberated. For another emitter, the light of wavelength $600\: nm$ is sufficient for liberating photoelectrons. The ratio of the work function of the two emitters, is

asked Dec 27, 2013 by thanvigandhi_1

1 answer

From this figure describing photoelectric effect, we may infer correctly that :

asked Dec 27, 2013 by thanvigandhi_1

1 answer

De Broglie wavelength of photoelectrons is $1\: A^{\circ}$ . What is stopping potential?

asked Dec 27, 2013 by thanvigandhi_1

1 answer

In an accelerator experiment on high – energy collisions of electrons with positrons, a certain event is interpreted as annihilation of an electron – positron pair of total energy $10.2\: BeV$ into two $ \gamma$-rays of equal energy. What is the wavelength associated with each $ \gamma$-ray? $(1\; Bev = 10^9\: eV)$

asked Dec 27, 2013 by thanvigandhi_1

1 answer

Find the de Broglie $ \lambda$ of a neutron, in thermal equilibrium with matter, having an average $KE\: of \bigg(\large\frac{3}{2} \bigg)\: kT$ at $300 \: K.$

asked Dec 27, 2013 by thanvigandhi_1

1 answer

The typical de Broglie wavelength associated with a $He$ atom in $He$ gas at room temperature $(27^{\circ}C)$ and $1 \: atm$ pressure is $ \lambda$, and the mean separation between two atoms under these conditions is $r.$

asked Dec 27, 2013 by thanvigandhi_1

1 answer

Crystal diffraction experiments can be performed using X – rays, or electrons accelerated through appropriate voltage. Which probe has greater energy? (Take wavelength of probe = $1 A^{\circ}$ )

asked Dec 27, 2013 by thanvigandhi_1

1 answer

The distance of the point $(1,-5,9) $ from the plane $x-y+z=5$ measured along the line $x=y=z$ is ?

asked Dec 26, 2013 by rvidyagovindarajan_1

1 answer

The equation of the plane which is parallel to the plane $x-2y+2z-5=0$ and which is at a unit distance from origin is ?

asked Dec 26, 2013 by rvidyagovindarajan_1

1 answer

The equation of the plane passing through the line of intersection of the planes $x+2y+3z-2=0\:\:and\:\:x-y+z-3=0$ and which is at a distance of $\large\frac{2}{\sqrt 3}$ units from $(3,1,-1)$. is ?

asked Dec 26, 2013 by rvidyagovindarajan_1

1 answer

Monochromatic radiation of wavelength $640.2\: nm$ from a neon lamp irradiates photosensitive material made of cesium on tungsten. The stopping voltage is measured to be $0.54\: V$. The source is replaced by an iron source and its $427.2\: nm$ light irradiates then same photocell. Predict the new stopping voltage.

asked Dec 25, 2013 by thanvigandhi_1

1 answer

Ultraviolet light of wavelength $2271\: A^{\circ}$ from a $100\: W$ mercury source irradiates a photocell made of molybdenum metal. If the stopping potential is $-1.3\: V$,will the photocell respond to a high intensity $(10^{-5}W/m^2)$ red light of wavelength $632.8\: A^{\circ}$ produced by a He-Ne laser?

asked Dec 25, 2013 by thanvigandhi_1

1 answer

Find the number of photons entering the pupil of our eye per second corresponding to the minimum intensity of white light that humans can perceive $(10^{-10}W/m^2$ ).( Assume area of pupil to be $0.4 cm^2$ , and average frequency of white light to be $6 \times 10^{14}Hz)$

asked Dec 25, 2013 by thanvigandhi_1

1 answer

An electron gun with its collector at a potential of $100 \;V$ fires out electrons in a spherical bulb 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 electrons in a circular orbit of radius $12\; cm$. Find e/m of the electron.

asked Dec 25, 2013 by thanvigandhi_1

1 answer

What is the de Broglie wavelength of a nitrogen molecule in air at $300\; K?$ Assume molecule is moving with the rms speed of molecules at this temp. At. mass of $N= 14.0076 \; u$

asked Dec 25, 2013 by thanvigandhi_1

1 answer

The $ \lambda$ of light from the spectral emission line of sodium is $589\: nm$. Find the $KE$ at which an electron would have the same de Broglie wavelength.

asked Dec 25, 2013 by thanvigandhi_1

1 answer

The momentum of the electrons accelerated through a potential difference of $56\; V$ is

asked Dec 25, 2013 by thanvigandhi_1

1 answer

Light of wavelength $488\: nm$ is produced by an argon laser which is used in the photoelectric effect. When light from this spectral line is incident on the emitter, the cut-off potential of photoelectrons is $0.38\: V$. The work function of the material from which the emitter is made is

asked Dec 24, 2013 by thanvigandhi_1

1 answer

In an experiment on photoelectric effect, the slope of the cut-off voltage versus frequency of incident light is found to be $4.12 \times 10^{-15}Vs$. Calculate the value of Planck’s constant.

asked Dec 24, 2013 by thanvigandhi_1

1 answer

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