what are photocathode used for?
155594
A photocathode is a negatively charged electrode in a light detection device such as a photomultiplier or phototube that is coated with a photosensitive compound. When this is struck by a quantum of light (photon), the absorbed energy causes electron emission due to the photoelectric effect.
566859
A photoelectric smoke detector is characterized by its use of light to detect fire. Inside the alarm, there's a light-sensing chamber. In this chamber, an LED light shoots a beam of light in a straight light across the chamber.
474855
The cyclotron is a device which is used to accelerate charged particles such as protons, deutrons, alpha particles, etc. to very high energy. The principle on which a cyclotron works is based on the fact that an electric field can accelerate a charged particle and a magnetic field can throw it into a circular orbit.
909761
CCDs. Charge coupled devices, or CCDs, are sensitive detectors of photons that can be used in telescopes instead of film or photographic plates to produce images. CCDs were invented in the late 1960s and are now used in digital cameras, photocopiers and many other devices.
1149318
Alkali metals have lower ionization energy than their counterparts and hence have higher chance of emitting electrons when a radiation falls on them. So they are used in photoelectric cells so that they easily emit electron when energy containing photons in sunlight strikes them.
812710
Cyclotrons were used to produce all the synthetic elements in the periodic table, namely those with atomic number 95 and above. Several of these elements were discovered using the Berkeley cyclotron and the names of the elements berkelium, californium and americium bear witness to this.
1290507
A Geiger counter, or a Geiger-Muller tube, is used for detecting and measuring alpha, beta and gamma radiation. It consists of a pair of electrodes with a high voltage running between them. ... Radiation entering the tube ionizes the gas. Electrons and ions are attracted to the electrodes, producing an electric current.
927176
A CRT monitor contains millions of tiny red, green, and blue phosphor dots that glow when struck by an electron beam that travels across the screen to create a visible image. ... Electrons are negative. The anode is positive, so it attracts the electrons pouring off the cathode.
425824
['They have a shorter wavelength of the electromagnetic spectrum.', 'Requires high voltage to produce X-Rays.', 'They are used to capture the human skeleton defects.', 'They travel in a straight line and do not carry an electric charge with them.', 'They are capable of travelling in a vacuum.']
248946
Like a wave, cathode rays travel in straight lines, and produce a shadow when obstructed by objects. Ernest Rutherford demonstrated that rays could pass through thin metal foils, behavior expected of a particle. These conflicting properties caused disruptions when trying to classify it as a wave or particle.
548052
Night vision devices gather existing ambient light (starlight, moonlight or infra-red light) through the front lens. This light, which is made up of photons goes into a photocathode tube that changes the photons to electrons.
119414
The slope of a plot of stopping potential versus frequency is the value of the ratio, h/e. See Figure 1. The photoelectric effect is almost instantaneous. Once the light shines on the cathode, photoelectrons will be emitted in less than a nanosecond.
1317094
D cells are typically used in high current drain applications, such as in large flashlights, radio receivers and transmitters and other devices that require an extended running time. A D cell may be either rechargeable or non-rechargeable. Its terminal voltage and capacity depend upon its cell chemistry.
714373
[' A source of free electrons.', ' A means to provide the electrons with high kinetic (motion) energy.', ' A method to concentrate the electrons into a beam.', ' A suitable material to rapidly decelerate the electrons.']
186837
These resistors are used as light sensors and the applications of LDR mainly include alarm clocks, street lights, light intensity meters, burglar alarm circuits.
909253
alpha emitters are used to kill organs that are failing, and to kill spies. They also make helium atoms for balloons. beta is used in smoke detectors, and some medical uses. gamma is used to detect the integrity of a well casing, to sterilize medical product or food, and to kill well defi.
923814
Ultraviolet (UV) light technologies are used for multiple purposes in forensic investigations, including authenticating paintings and other fine art, authenticating signatures, analyzing questioned documents , illuminating latent fingerprints at crime scenes and trace evidence on clothing, analyzing ink stains, and ...