Advertisements
Advertisements
प्रश्न
Describe the construction of photoelectric cell.
Advertisements
उत्तर १
A photoelectric cell is device which converts light energy into electrical energy. It works on the principle of photoelectric effect.
Construction : A photoelectric cell consist a small evacuated bulb. A thin layer of an alkali metal is deposited on inner surface of the bulb. The bulb is made of quartz, if cell is used with ultraviolet light. If the cell is to be used with visible light only. the bulb is made of ordinary glass. A small portion of the surface of bulb is left uncoated and serves as a window for incoming light. The coated surface of the bulb acts as cathode. The anode is in shape of sphere.
उत्तर २
Construction —
- Photocell consists of evacuated glass tube containing two electrodes emitter (K) and collector (A).
- The emitter is shaped in the form of a semi hollow cylinder. It is always kept at a negative potential.
- The collector is in the form of a matal rod and fixed at the axis of the semi-cylinderical emitter. The collector is always kept as a positive potential.
- The glass tube is fitted on non-metallic base and pins are provided at the base for external connection.
Working —
- The emitter is connected to negative terminal and collector is connected to positive terminal of a battery.
- A radiation of frequency more than threshold frequency of material of emitter is made incident on the emitter. Photo-emissions take place. The photoelectrons are attracted towards the collector which is positive w.r.t the emitter. Thus, current flows in the circuit.
- If the intensity of incident radiation is increased, the photoelectric current increases.
APPEARS IN
संबंधित प्रश्न
The wavelength of light from the spectral emission line of sodium is 589 nm. Find the kinetic energy at which
(a) an electron, and
(b) a neutron, would have the same de Broglie wavelength.
What is the de Broglie wavelength of a ball of mass 0.060 kg moving at a speed of 1.0 m/s?
For what kinetic energy of a neutron will the associated de Broglie wavelength be 1.40 × 10−10 m?
Find the de Broglie wavelength of a neutron, in thermal equilibrium with matter, having an average kinetic energy of `(3/2)` kT at 300 K.
What is the de Broglie wavelength of a nitrogen molecule in air at 300 K? Assume that the molecule is moving with the root-mean square speed of molecules at this temperature. (Atomic mass of nitrogen = 14.0076 u)
Obtain the de Broglie wavelength associated with thermal neutrons at room temperature (27°C). Hence explain why a fast neutron beam needs to be thermalised with the environment before it can be used for neutron diffraction experiments.
Why photoelectric effect cannot be explained on the basis of wave nature of light? Give reasons.
What are matter waves?
Show with the help of a labelled graph how their wavelength (λ) varies with their linear momentum (p).
Sodium and copper have work function 2.3 eV and 4.5 eV respectively. Then, the ratio of the wavelengths is nearest to ______.
Which one of the following deflect in electric field
An electron (mass m) with an initial velocity `v = v_0hati (v_0 > 0)` is in an electric field `E = - E_0hati `(E0 = constant > 0). It’s de Broglie wavelength at time t is given by ______.
Relativistic corrections become necessary when the expression for the kinetic energy `1/2 mv^2`, becomes comparable with mc2, where m is the mass of the particle. At what de Broglie wavelength will relativistic corrections become important for an electron?
- λ = 10 nm
- λ = 10–1 nm
- λ = 10–4 nm
- λ = 10–6 nm
A particle A with a mass m A is moving with a velocity v and hits a particle B (mass mB) at rest (one dimensional motion). Find the change in the de Broglie wavelength of the particle A. Treat the collision as elastic.
The ratio of wavelengths of proton and deuteron accelerated by potential Vp and Vd is 1 : `sqrt2`. Then, the ratio of Vp to Vd will be ______.
A particle of mass 4M at rest disintegrates into two particles of mass M and 3M respectively having non zero velocities. The ratio of de-Broglie wavelength of particle of mass M to that of mass 3M will be:
How will the de-Broglie wavelength associated with an electron be affected when the accelerating potential is increased? Justify your answer.
The graph which shows the variation of `(1/lambda^2)` and its kinetic energy, E is (where λ is de Broglie wavelength of a free particle):
Which phenomena support the particle model of light?
What is another name for matter waves?
Which relation gives the de Broglie wavelength of a particle of mass \[m\] moving with speed \[v\]?
In \[\lambda=\frac{h}{mv}\], what do \[m\] and \[v\] represent, respectively?
Which wave quantities did de Broglie relate to the particle quantities energy and momentum?
Rearranging \[p=\frac{h}{\lambda}\] gives which expression?
Why did de Broglie propose an associated wavelength for a moving particle?
Which phenomenon does the concept of matter waves help explain?
What value of Planck's constant is used in the de Broglie wavelength calculations?
What de Broglie wavelength is obtained for the electron?
