6. The wavelength of X-rays is of the order of
A. 10 micron
B. 1 angstrom
C. 1 cm
D. 1 m
7. Mesons are found in
A. Laser beam
B. X-rays
C. Gamma rays
D. Cosmic rays
8. Which radioactive pollutant has recently drawn to public, due to its occurrence in the building material?
A. Thorium
B. Radium
C. Plutonium
D. Radan
9. Which of the following shows the masses of the three elementary particles in decreasing order?
A. Leptons, Baryons, Mesons
B. Mesons, Baryons, Leptons
C. Baryons, Mesons, Leptons
D. Leptons, Mesons Baryons
10. What is the wavelength of visible spectrum?
A. 8500 – 9800 angstrom
B. 7800 – 8000 angstrom
C. 3900 – 7600 angstrom
D. 1300 – 3000 angstrom