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प्रश्न
With the help of a circuit diagram describing an experiment to study the photoelectric effect.
Explain the experimental set-up of the photoelectric effect.
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उत्तर
Schematic of experimental set-up for the photoelectric effect
- A laboratory experimental set-up for the photoelectric effect consists of an evacuated glass tube with a quartz window.
- The glass tube contains photosensitive metal plates. One is the emitter E and another plate is the collector C.
- The emitter and collector are connected to a voltage source whose voltage can be changed and to an ammeter to measure the current in the circuit.
- A potential difference of V, as measured by the voltmeter, is maintained between the emitter E and collector C. Generally, C (the anode) is at a positive potential with respect to the emitter E (the cathode). This potential difference can be varied, and C can even be at a negative potential with respect to E.
- When the anode potential (V) is positive, it accelerates the electrons. This potential is called accelerating potential. When the anode potential (V) is negative, it retards the flow of electrons. This potential is known as retarding potential.
- A source S of monochromatic light of sufficiently high frequency (short wavelength ≤ 10–7 m) is used.
संबंधित प्रश्न
Choose the correct option.
Polychromatic (containing many different frequencies) radiation is used in an experiment on the photoelectric effect. The stopping potential ______.
What is the photoelectric effect?
Can microwaves be used in the experiment on photoelectric effect?
Is it always possible to see the photoelectric effect with a red light?
Explain the inverse linear dependence of stopping potential on the incident wavelength in a photoelectric effect experiment.
Using the values of work function given in the following table, tell which metal will require the highest frequency of incident radiation to generate photocurrent.
Typical values of work function for some common metals
| Metal | Work function (in eV) |
| Potassium | 2.3 |
| Sodium | 2.4 |
| Calcium | 2.9 |
| Zinc | 3.6 |
| Silver | 4.3 |
| Aluminium | 4.3 |
| Tungsten | 4.5 |
| Copper | 4.7 |
| Nickel | 5.0 |
| Gold | 5.1 |
Find the kinetic energy of the emitted electron, if in photoelectric effect energy of incident Photon is 4 eV and work function is 2.4 eV.
State Einstein photoelectric equation.
The energy of the incident photon on the metal surface is 3 W and then 5 W, where W is the work function for that metal. The ratio of velocities of emitted photoelectrons is ______.
The maximum velocity of photoelectron emitted is 4.8 m/s. If the e/m ratio of the electron is 1.76 × 1011 C/kg, then stopping potential is given by ______
The following graph shows the stopping potential V0 versus frequency v for photoelectric emission from two metals A and B. The slope of each of the lines gives ______
When a photon enters glass from air, which one of the following quantity does not change?
In photoelectric effect, for a light of different intensities but of same frequency, the stopping potential for a given metal is ____________.
Light of frequency 2 times the threshold frequency is incident on a photo sensitive material. If the frequency is made `1/3`rd and intensity is doubled then the photocurrent will ______.
The photon of frequency vis incident on a metal surface whose threshold frequency is v0. The kinetic energy of the emitted photoelectrons will be ____________.
Following graphs show the variation of stopping potential corresponding to the frequency of incident radiation (F) for a given metal. The correct variation is shown in graph (v0 = Threshold frequency).
Which one of the following statements ts INCORRECT for stopping potential in photoelectric emission?
When a certain metallic surface is illuminated with monochromatic light of wavelength '`lambda`', the stopping potential for photoelectric effect is '3V0'. If the same surface is illuminated with a light of wavelength '`2 lambda`', the stopping potential is found as 'V0'. The threshold wavelength for this surface is ____________.
The ratio of slopes m1: ro2 of the lines given in the following graphs is, ______.
A light of frequency 'v' is incident on the metal surface whose threshold frequency is 'v0'. If v = v0, then [c = speed of light in medium] ____________.
Is it always necessary to use red light to get a photoelectric effect?
The radiation corresponding to the 3 → 2 transition of a hydrogen atom falls on a gold surface to generate photoelectrons. These electrons are passed through a magnetic field of 5 × 10-4 T. Assume that the radius of the largest circular path followed by these electrons is 7 mm, and the work function of the metal is ______.
(Mass of electron = 9.1 × 10-31 kg)
The stopping potential in the context of photoelectric effect depends on the following property of incident electromagnetic radiation ______.
The radiation emitted, when an electron jumps from n = 3 to n = 2 orbit is a hydrogen atom, falls on a metal to produce photoelectron. The electrons from the metal surface with maximum kinetic energy are made to move perpendicular to a magnetic field of `1/320`T in a radius of 10-3m. Find the 320 work function of metal:
Photoelectric emission is observed from a metallic surface for frequencies ν1 and ν2 of the incident light rays (ν1 > ν2). If the ratio of the maximum value of the kinetic energy of the photoelectrons emitted in the first case to that in the second case is 2 : K, then the threshold frequency of the metallic surface is ______.
Define photoelectric work function of a metal.
Give Einstein's explanation of the photoelectric effect.
Explain the formation of clouds at high altitude.
A parallel plate capacitor with air between the plates has capacitance 9 pF. The separation between the plates becomes thrice and the space between them is filled with a medium of dielectric constant 6. The capacitance becomes 'x' pF. The value of 'x' is ______.
