The mass of proton is 1.0073 u and that of neutron is 1.0087 u (u = atomic mass unit). The binding energy of $^{4}_{2}He$ is
Given, mass of helium nucleus $\approx4.0015 u.$
- 28.4 MeV
- 0.061 u
- 0.0305 J
- 0.0305 erg
The Correct Option is A
Solution and Explanation
Mass of 2 protons $=2 \times 1.0073 $
$ =2.0146 u$
Mass of 2 neutrons $=2 \times 1.0087$
$ =2.0174 u$
Total mass of 2 protons and 2 neutrons
=(2.0146+ 2.0174)u =4.032u
Mass of helium nucleus= 4.0015 u
Thus, mass defect is lacking of mass in forming the helium
nucleus from 2 protons and 2 neutrons.
$\therefore ?m=mass \, defect $
$ $ = ( 4.032 - 4.0015 )u
$ $ = 0.0305 u
$ $ = 0.0305amu
but $ 1 \, amu=931 MeV$
Hence, binding energy
$ ? E=(?m) \times 931$
$ =0.0305 \times 931=28.4 MeV $
Top Questions on Atoms
- An atom is subjected to a weak uniform magnetic field \( B \). The number of lines in its Zeeman spectrum for the transition from \( n = 2, l = 1 \) to \( n = 1, l = 0 \) is
- The spectral series which corresponds to the electronic transition from the levels n2 = 5, 6,… to the level n1 = 4 is
- The ratio of the shortest wavelength of Balmer series to the shortest wavelength of Lyman series for hydrogen atom is :
- In hydrogen like system the ratio of coulombian force and gravitational force between an electron and a proton is in the order of:
- If the wavelength of the first member of the Lyman series of hydrogen is \( \lambda \). The wavelength of the second member will be:
Questions Asked in BHU UET exam
- Excitation of chlorophyll in light is
- BHU UET - 2012
- Photosynthesis in higher plants
- Triticale, the first man made cereal crop, has been obtained by crossing wheat with
- BHU UET - 2012
- Strategies For Enhancement in Food Production
- Bryophytes are known as amphibians of plant kingdom because
- BHU UET - 2012
- Kingdom Plant
- In Cycas, dehiscence of microsporangium occurs when pollen grains are at
- BHU UET - 2012
- Kingdom Plant
- Potato spindle tuber disease is caused by
- BHU UET - 2012
- biological classification
Concepts Used:
Atoms
- The smallest unit of matter indivisible by chemical means is known as an atom.
- The fundamental building block of a chemical element.
- The smallest possible unit of an element that still has all the chemical properties of that element.
- An atom is consisting of a nucleus surrounded by one or more shells of electrons.
- Word origin: from the Greek word atomos, which means uncuttable, something that cannot be divided further.
All matter we encounter in everyday life consists of smallest units called atoms – the air we breath consists of a wildly careening crowd of little groups of atoms, my computer’s keyboard of a tangle of atom chains, the metal surface it rests on is a crystal lattice of atoms. All the variety of matter consists of less than hundred species of atoms (in other words: less than a hundred different chemical elements).
Every atom consists of an nucleus surrounded by a cloud of electrons. Nearly all of the atom’s mass is concentrated in its nucleus, while the structure of the electron cloud determines how the atom can bind to other atoms (in other words: its chemical properties). Every chemical element can be defined via a characteristic number of protons in its nucleus. Atoms that have lost some of their usual number of electrons are called ions. Atoms are extremely small (typical diameters are in the region of tenths of a billionth of a metre = 10-10 metres), and to describe their properties and behaviour, one has to resort to quantum theory.