Advertisements
Advertisements
Question
Iron emits Kα X-ray of energy 6.4 keV. Calculate the times taken by an iron Kα photon to cross through a distance of 3 km.
(Use Planck constant h = 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
Advertisements
Solution
Given:
Energy of the X-ray, E = 6.4 keV
Distance travelled by the photon, d = 3 km = 3 `xx ` 103 m
Time taken by the photon to cross the distance of 3 km is given by
`t = "Distance"/"Speed" = (3 xx 10^3)/(3 xx 10^8)`
`t = 10^-5 "s" = 10 xx 10^-6 "s"`
`t = 10 mus`
Both the Kα photon and X-ray will take the same time, that is, 10 μs , to cross the distance of 3 km.
APPEARS IN
RELATED QUESTIONS
Identify the part of the electromagnetic spectrum which is suitable for radar system used in aircraft navigation.
Identify the part of the electromagnetic spectrum which is:
produced by bombarding a metal target by high speed electrons.
If the earth did not have an atmosphere, would its average surface temperature be higher or lower than what it is now?
What is the range of the wavelength of the following electromagnetic waves?
(a)X-rays,
How are X-rays produced?
In a Coolidge tube, electrons strike the target and stop inside it. Does the target get more and more negatively charged as time passes?
The Kβ X-rays from certain elements are given below. Draw a Moseley-type plot of √v versus Z for Kβ radiation.
| Element | Ne | P | Ca | Mn | Zn | Br |
| Energy (keV) | 0.858 | 2.14 | 4.02 | 6.51 | 9.57 | 13.3 |
Heat at the rate of 200 W is produced in an X-ray tube operating at 20 kV. Find the current in the circuit. Assume that only a small fraction of the kinetic energy of electrons is converted into X-rays.
The wavelength of Kα X-ray of tungsten is 21.3 pm. It takes 11.3 keV to knock out an electron from the L shell of a tungsten atom. What should be the minimum accelerating voltage across an X-ray tube having tungsten target which allows production of Kα X-ray?
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
If the operating potential in an X-ray tube is increased by 1%, by what percentage does the cutoff wavelength decrease?
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
When 40 kV is applied across an X-ray tube, X-ray is obtained with a maximum frequency of 9.7 × 1018 Hz. Calculate the value of Planck constant from these data.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
Continuous X-rays are made to strike a tissue paper soaked with polluted water. The incoming X-rays excite the atoms of the sample by knocking out the electrons from the inner shells. Characteristic X-rays are analysed and the intensity is plotted against the wavelength. Assuming that only Kα intensities are detected, list the elements present in the sample from the plot. Use Moseley's equation v − (25 × 1014Hz)(Z − 1)2.
(Use Planck constant h = 6.63 × 10-34 Js= 4.14 × 10-15 eVs, speed of light c = 3 × 108 m/s.)
Name the scientist who discovered Visible light
Answer briefly.
Why are microwaves used in radar?
Calculate the wavelength of a microwave of a frequency of 8.0 GHz.
The area to be covered for T.V telecast is doubled then the height of transmitting antenna (T.V tower) will have to be:-
All components of the electromagnetic spectrum in a vacuum have the same ______
Name one radiation having the wavelength longer than the wavelength of these radiations.
In an atom X, electrons absorb the energy from an external source. This energy “excites” the electrons from a lower-energy level to a higher-energy level around the nucleus of the atom. When electrons return to the ground state, they emit photons.
The figure below is the energy level diagram of atom X with three energy levels, E1 = 0.00eV, E2 = 1.78eV and E3 = 2.95eV. The ground state is considered 0 eV for reference. The transition of electrons takes place between levels E1 and E2.
- What wavelength of radiation is needed to excite the atom to energy level E2 from E1?
- Suppose the external source has a power of 100 W. What would be the rate of photon emission?
