10 Question-Answer on electromagnetic spectrum
1. The wavelength of X-rays is of the order of:
(a) 1 metre
(b) 1 cm
(c) 1 micron
(d) 1 angstrom
Ans: ( d)
2. Which of the following is the largest wave?
(a) X-rays
(b) ϒ – rays
(c) Microwaves
(d) Radio waves
Ans : (d)
3. In which of the following, emission of electrons does not take place
(a) Thermionic emission
(b) X-ray emission
(c) Photoelectric emission
(d) Secondary emission
Ans: ( b)
4. Molybedenum is used as a target element for the production of X-xrays because it is
(a) Light and can easily deflect electrons
(b) Light and can absorb electrons
(c) A heavy element with a high melting point
(d) An element heaving high thermal conductivity
Ans: (c)
5. Which of the following electromagnetic waves have the largest wavelength
(a) Heat waves
(b) Light waves
(c) Radio waves
(d) Microwaves
Ans: ( c)
6. Which of the following is of shortest wave-length?
(a) X-rays
(b) Y-rays
(c) Microwaves
(d) Radio waves
Ans; (b)
7. Radio waves do not penetrate in the band of
(a) Ionosphere
(b) Mesosphere
(c) Troposphere
(d) Stratosphere
Ans: (a)
8. The wavelength of X-rays lies between
(a) Maximum to finite limits
(b) Minimum to certain limits
(c) Minimum to infinite limits
(d) Infinite to finite limits
Ans: ( b)
9. The penetrating power of X-rays increases with the increase in its
(a) Velocity
(b) Intensity
(c) Frequency
(d) Wavelength
Ans: (c)
10. Hydrogen atom does not emit X-rays because
(a) It has single electron
(b) It has no neutron
(c) It has single neutron
(d) Its energy levels are too close to each other
Ans: ( a)