10 Question-Answer on X-rays
1. If the X-ray tube is working at 20 kV then the minimum wavelength of X-rays will be:
(a) 0.31 A
(b) 0.62 A
(c) 0.93 A
(d) 0.47 A
Ans: (b)
2. The maximum distance between interatomic lattice planes is 15 A. the maximum wavelength of X-rays which are diffracted by this crystal will be
(a) 15 A
(b) 20 A
(c) 30 A
(d) 45 A
Ans: ( c)
3. For which of the following voltages will the wavelength of emitted X-rays will be minimum?
(a) 10 kV
(b) 20 k V
(c) 30 k V
(d) 40 kV
Ans: ( d)
4. The wavelength of characteristic X-rays depends upon
(a) Temperature of target
(b) Size of target
(c) Atomic number of target
(d) Mass of target
Ans: ( c)
5. The energy of X-rays of wavelength 5 A in eV will be
(a) 2.48
(b) 24.8
(c) 0.248
(d) 0.0248
Ans: (b)
6. In an X-ray tube if the electrons are accelerated through 140 kV, then anode current obtained is 30mA. If the whole energy of electrons is converted into heat then the rate of production of heat (in calorie/sec) at anode will be:
(a) 420
(b) 640
(c) 1000
(d) 1200
Ans: ©
7. The lattice constant of a crystal is 2 A. the maximum wavelength of X-rays which can be analyzed by this crystal will be:
(a) 2A
(b) 3A
(c) 4A
(d) 8A
Ans: (c)
8. The X-rays of wavelength 0.5 A are scattered by a target. What will be the energy of incident X-rays, if these are scattered at an angle of 72˚?
(a) 12.41 keV
(b) 6.2 keV
(c) 18.6 keV
(d) 24.82 keV
Ans: ( d)
9. 50 % of X-rays obtained from a Coolidge tube pass through 0.3 mm thick aluminium foil. If the potential difference between the target and the cathode is increased, then the fraction of X-rays passing through the same foil will be
(a) 50%
(b) >50%
(c) <50%
(d) Not sure
Ans: (b)
10. The glancing angle in a X-ray diffraction is 30˚ and the wavelength of X-rays used is 20 nm. The interplanar spacing of the crystal diffracting these X-rays will be:
(a) 40 nm
(b) 20 nm
(c) 15 nm
(d) 10 nm
Ans: (b)