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12 eV energy is given to electron in third orbit of H-atom, then final energy of electron when it ionise from third orbit, is

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Important Questions on Modern Physics

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BITSAT
IMPORTANT
EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 18 - Modern Physics>BITSAT 2018>Q 3
Some amount of a radioactive substance (half-life =10 days ) is spread inside a room and consequently, the level of radiation becomes 50 times the permissible level for normal occupancy of the room. After how many days will the room be safe for occupation?
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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 18 - Modern Physics>BITSAT 2018>Q 4
The frequency and the intensity of incident beam of light falling on the surface of a photoelectric material is increased by a factor of two. This will
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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 18 - Modern Physics>BITSAT 2018>Q 5
When photon of energy 4.0 eV strikes the surface of a metal A, the elected photoelectrons have maximum kinetic energy TA eV and de-Broglie wavelength λA. The maximum kinetic energy of photoelectron liberated from another metal B by photon of energy 4.50 eV is TB=TA-1.50 eV. If the de-Broglie wavelength of these photoelectrons λB=2λA, then choose the correct statement(s).
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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 18 - Modern Physics>BITSAT 2017>Q 6
The de-Broglie wavelength of a proton (charge =1.6×10-19 C,m=1.6×10-27 kg) accelerated through a potential difference of 1 kV is 
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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 18 - Modern Physics>BITSAT 2017>Q 7
The total energy of an electron in the first excited state of hydrogen is about -3.4 eV. Its kinetic energy in this state is 
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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 18 - Modern Physics>BITSAT 2017>Q 8
The activity of a radioactive sample is measured as N0 counts per minute at t=0 and N0e counts per minute at t=5 min. The time (in minutes) at which the activity reduces to half its value is
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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 18 - Modern Physics>BITSAT 2017>Q 9
Monochromatic radiation of wavelength λ is incident on a hydrogen sample in ground state. Hydrogen atom absorbs a fraction of light and subsequently emits radiations of six different wavelengths. The wavelength λ is
HARD
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EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 18 - Modern Physics>BITSAT 2017>Q 10
An α-particle after passing through potential difference of V volt collides with a nucleus. If the atomic number of the nucleus is Z, then distance of closest approach is