Choose the appropriate word. anode, doubling, ejected, immaterial, imparted, measure, vacuum, work function 1
The positive terminal of the battery is called the ……(anode)……. 2
The photoelectric effect occurs in a ……….(vacuum)……… tube on certain conditions. 3
The ………(work function)…… determines the extent to which photoemission will occur according to the Einstein’s photoelectric theory. 4
The photon’s energy is …….(imparted)………. to an electron. 5
The number of photons striking the metallic surface is ……..(immaterial)…….. in determining the energy of the ………(ejected)……… electron. 6
………(Doubling)………. the intensity of the radiation doubles the number of photoelectrons emitted. 7
The ammeter is an instrument to ……….(measure)…….. electric current. Choose the best option to complete the sentence. 1. Albert Einstein called the photon a)
a light quantum. b)
an electron. c)
a photon. 2. Particles of light are called … a) protons. b) photons. c) electrons. 3.
The term photon was coined by … a) Albert Einstein. b) Gilbert N.Lewis. c) Ernest Rutherford. 4. Gamma rays were proved to be a form of light by … a) Gilbert N.Lewis. b) Villard. c) Rutherford and Andrade. 5. The photon … a) is massive. b) has no electric charge. c) is denoted by the symbol of the Greek letter λ. 6. Photons are absorbed … a) in nuclear transitions to a higher energy level. b) when a nucleus jumps from a higher to lower energy level. c) when a charge is accelerated. 7. A photon can be denoted by … a) the symbol of the Greek letter alpha α b) the symbol of the Greek letter gamma γ. c) the symbol of the Greek letter lamda λ 8. Now photons are much more often symbolized by a) Hυ b) Hc c) Hq 9. As for its basic properties, the photon
a) is always moving
b) is always still
c) is either moving or still
10. Photons are emitted
a) only under experimental conditions
b) in many natural processes
c) onlyin nuclear plants
Read the sentences and decide whether they are true (T) or false
(F).
1…..T……Photons are particles that make up light. 2. ….F…... The photon was given the name of a “light quantum” by Gilbert N. Lewis. 3…...F……The modern name photon derives from the Greek word for wave. 4……F……Lewis’ speculative theory in which photons were described as “uncreatable and indestructible”was accepted by most of the physicists. 5. …F……. A photon can be denoted by the symbol of the Greek letter lamda λ. 6. …T…… Now photons are much more often symbolized by hυ. 7. …T…… As for its basic properties, the photon is always on the move. 8……F…… The photon has an electrical charge. 9. …..F…… The photon has three possible polarisation states. 10. …T…… Photons are absorbed in the time­reversed processes. Read the sentences and decide whether they are true (T) or false (F).
1…..F……Photons are particles that make up a solid body. 2. ….T…... The photon was given the name of a “light quantum” by Albert Einstein. 3…...T……The modern name photon derives from the Greek word for light. 4……T……Lewis’ speculative theory in which photons were described as “uncreatable and indestructible”was never accepted. 5. …F……. A photon can be denoted by the symbol of the Greek letter alpha α. 6. …F……… Now photons are much more often symbolized by hα. 7. …F……... As for its basic properties, the photon is always still. 8……T…… The photon has no electrical charge. 9. …..T……The photon has two possible polarisation states. 10. …T……Photons are usually characterised by three continuous parameters. Read the sentences and decide whether they are true (T) or false
(F).
1…F……..Photons are usually characterised by two continuous parameters. 2.….T……Photons are particles that make up light. 3. ….T…... The first conclusive evidence that light was made up of photons was received in 1977. 4…...T…… A photon can be denoted by the symbol of the Greek letter gamma γ. 5. …T…… .The modern name photon derives from the Greek word for light. 6……T……Lewis’ speculative theory in which photons were described as “uncreatable and indestructible”was never accepted. 7. …T……. Now photons are much more often symbolized by hυ, the energy of a photon, where h is Planck’s constant and the Greek letter υ is the photon’s frequency. 7. …F……... Gamma rays were discovered and named by Villard in 1990. 8……F…… The photon weighs two milligrams. 9. ….F……. The photon decays in an empty space. 10. …T……The photon has an ability to carry energy and momentum.
Read the sentences and decide whether they are true (T) or false
(F).
1. …T……. Now photons are much more often symbolized by hυ, the energy of a photon, where h is Planck’s constant and the Greek letter υ is the photon’s frequency. 2. …T……….The photon has a constant speed for all observers – the same as the speed of light. 3. …T……Gamma rays were shown to be a form of light by Rutherford and Andrade in 1914. 4. …...T…… A photon can be denoted by the symbol of the Greek letter gamma γ. 5…...T……Photons are particles that make up light. 6…...F……The modern name photon derives from the Greek word for wave. 7…...F…... The first conclusive evidence that light was made up of photons was received in 1987. 8. ….T….. Photons are absorbed in atomic transitions to a higher energy level. 9. .....T....... Photons are emitted when a particle and its antiparticle are annihilated. 10…F…. When in a vacuum, the photon has a different speed for all observers.