B.Sc. F.Y. Sem-II
Unit : I
Atomic Structure (M.C.Q's)
1. Cathode rays are deflected by
a) electric field only
b) magnetic field only
c) electric and magnetic field
d) none of these
Answer : c
2. The e/m value for the particles constituting cathode rays is the same regardless of
a) the gas present in cathode rays tube
b) the metal of which cathode was made
c) both of these
d) none of these
Answer : c
3. The charge of mass ration (e/m) of positive particles
a) varies with the nature of gas in discharge tube
b) is independent of the gas in discharge tube
c) is constant
d) none of the above
Answer : a
4. A sub atomic particle which has one unit mass and one unit positive charge is known as
a) hydrogen atom
b) neutron
c) electron
d) proton
Answer : d
5. Atomic number of an element is equal to the number of ______ in the nucleus of the atom.
a) neutrons
b) protons
c) both the neutrons and protons
d) electrons
Answer : b
6. The mass number of an atom is equal to the number of ____ in the nucleus of an atom.
a) protons
b) neutrons
c) electrons
d) nucleons
Answer :d
7. If Z is the number of proton and A the number of nucleons, then the number of neutrons is an atom is given
a) A + Z
b) A - Z
c) Z - A
d) none of these
Answer : b
8. The mass number of proton and A the number of nucleons, then the number of neutrons is an atom is given
a) 15
b) 16
c) 31
d) 46
Answer : b
9. In a sodium atom (atomic number = 11 and mass number = 23), the number of neutrons is
a) equal to the number of protons
b) less than the number of protons
c) greater than the number of protons
d) none of these
Answer : c
10. Which of the following is not correct for electromagnetic waves?
a) the wavelength is the distance between two successive crests
b) the frequency is the number of waves which pass a given point in one second
c) the velocity of a water is the distance covered by the particular wave in one second
d) all electromagnetic waves have equal wavelengths
Answer : d
11. The unit in which wave number is measured
a) hertz
b) sec-1
c) nanometer
d) cm-1
Answer : d
12. In the spectrum of hydrogen atom, the series which falls in ultraviolet region is
a) Lyman series
b) Balmer series
c) Paschen series
d) Brackett series
Answer :b
13. The Balmer series in the spectrum of hydrogen atoms falls in
a) ultraviolet region
b) visible region
c) infrared region
d) none of thses
Answer : b
14. When a beam of light of sufficiently high frequency is allowed to strike a metal surface in vacuum, electron are rejected from the metal surface. This phenomenon is called
a) Black body radiation
b) Photoelectric effect
c) Zeeman effect
d) Stark effect
Answer : b
15. In photoelectric effect, the kinetic energy of the photoelectrons increases linearly with the
a) wavelength of the incident light
b) frequency of the incident light
c) velocity of the incident light
d) none of these
Answer : b