Physics, 09.09.2020 14:01 trisngle2565
The ratio of thermal conductivity of two rods of different material is 5: 4. The two rods of same area of
cross-section and same thermal resistance will have the lengths in the ratio
A: 4:5
B: 9:1
C: 1:9
D: 5:4
Answers: 1
Physics, 22.06.2019 00:30
Comedians like to joke that the reason we havenââŹâ˘t been visited by intelligent life from elsewhere in the universe is that aliens have been monitoring earthââŹâ˘s broadcasts of intellectually embarrassing tv programs, like gilliganââŹâ˘s island, fear factor, the jersey shore, and the jerry springer showand so consider us far too primitive to merit a visit. letââŹâ˘s check the assertion that aliens could have been receiving them. tv programs are broadcast at a frequency of about 100mhz with about 100kw of total power in 30frames per second, which emanatesroughly uniformly in all directions. assume that interstellar space transmits these broadcasts without attenuation. no matter how smart they are, aliens would require at least one photon per frame to interpret our signals. findthe number of photons per unit time per unit area reaching a receiver on a possible planet in the nearest star system, which is about 4 light-years away (a light-year is the distance light travels in a year). if aliens aimed a receiver or detector directly at earth, how big (in diameter) would it have to be to receive a photon per frame
Answers: 2
Physics, 22.06.2019 12:30
Consider a hydrogen atom in the ground state. what is the energy of its electron? =e= jj now consider an excitedâstate hydrogen atom. what is the energy of the electron in the =5n=5 level? =e5= j
Answers: 3
Physics, 22.06.2019 12:50
Match each vocabulary term to its definition. 1. electrons neutral subatomic particles found in the nucleus of the atom 2. neutron lowest energy position of an electron in an atom 3. photon the path of an electron around the nucleus of an atom 4. ground state negatively charged, subatomic particles 5. protons packet of energy of specific size 6. element substance with only one type of atom 7. orbital positively charged, subatomic particles found in the nucleus of the atom
Answers: 1
Physics, 22.06.2019 15:00
Lightning is an example of what phenomenon? a release of a large amount of energy an absorption of a large amount of energy a natural electric circuit a natural electric current
Answers: 1
The ratio of thermal conductivity of two rods of different material is 5: 4. The two rods of same ar...
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