Advertisements
Advertisements
प्रश्न
A narrow beam of protons, each having 4.1 MeV energy is approaching a sheet of lead (Z = 82). Calculate:
- the speed of a proton in the beam, and
- the distance of its closest approach
Advertisements
उत्तर
(i) KE of 4.1 MeV proton = 4.1 × 106 × 1.6 × 10−19 J
Mass of proton = 1.67 × 10−27 kg
v2 = `(2"KE")/"m"`
Or, v2 = `(2 xx 4.1 xx 10^6 xx 1.6 xx 10^-19)/(1.67 xx 10^-27)`
Or, v2 = 7.85 × 1014
∴ v = 2.8 × 107 MeV
(ii) Energy of proton = 4.1 MeV
Atomic number (Z) of lead = 82
When the proton is at the distance of the closest approach (r), then,
KE of the system = 0
PE of the system = `"kZe"^2/"r"`
So, from the conservation of energy principle,
4.1 MeV = `0 + "kZe"^2/"r"`
O, r0 = `"kZe"^2/((4.1 xx 10^6 "e"))`
Or, r0 = `(9 xx 10^9 xx 82 xx "e"^2)/(4.1 xx 10^6"e")"m"`
∴ r0 = 288 × 10−16 m
r0 = 2.88 × 10−14
संबंधित प्रश्न
In the ground state of ______ electrons are in stable equilibrium, while in ______ electrons always experience a net force.
The positively charged part of the atom possesses most of the mass in ______.
In Geiger-Marsden experiment prediction was that ______.
The first line of Balmer series (Hα) in the spectrum of hydrogen is obtained when an electron of hydrogen atom goes from ______.
In a capillary tube, water rises by 1.2 mm. The height of water that will rise in another capillary tube having half the radius of the first is:
Which one of the following statements does not hold good when two balls of masses m1 and m2 undergo elastic collision?
The ratio of minimum to maxm wavelength in ballmer series is:-
According to Bohr model, magnetic field at centre (at the nucleus) of a hydrogen atom due to motion of electron in the ninth orbit is proportional to:
How is the size of a nucleus found experimentally? Write the relation between the radius and mass number of a nucleus.
When alpha particles are sent through a thin gold foil, most of them go straight through the foil, because ______.
