Structure of atom
unit -111
1. Which is not true with respect to cathode rays?
a) A stream of electrons
b) Charged particles
e) Move with speed same as that of light
d) Can be deflected by electric and magnetic fields
2. When electric discharge is passed through neon at low pressure, the colour of the glow is
a) Red
b) green
c) Yellow
d) orange
3. In Millikan's experiment, static electric charge on the oil drops has been obtained by shining \( X \)-rays. If the the static electric charge in the oil drop is \( -1.282 \times 10^{-18} C \), the number of electrons present in it is
a) 4
b) 6
c) 8
(NCERT Based)
4. Which of the following statement is not correct regarding cathode rays?
a) Cathode rays originate from the cathode
b) Charge and mass of the particles constituting cathode rays depends upon the nature of the gas
c) Charge and mass of the particles present does not depend upon the material of the cathode
d) The ratio charge/mass of the particles is much greater than that of anode rays.
5. Which of the following is never true for cathode rays?
a) They possess kinetic energy
b) They are electromagnetic waves
c) They product heat
d) They produce mechanical pressure.
6. What is wrong about anode rays?
a) Their e/m ratio is constant
b) They are deflected by electrical and magnetic field.
c) They are produced by ionization of molecules of the residual gas
d) They do not originate from the anode.
7. Canal rays is name for beam of
a. Electrons
b. protons
c. Neutrons
d. Positively charged ions.
8. The mass of a neutron is
a. Same as that of a proton
b. Slightly less than that of a proton
c. Slightly more than that of a proton
d. Much different from that of proton.
9. The mass of the neutron is of the order of
a. \( 10^{-23} kg \)
c. \( 10^{-24} kg \)
b. \( 10^{-26} kg \)
d. \( 10^{-27} kg \)
10. The mass of one mole of electrons is
a. \( 9.1 \times 10^{-28} g \)
b. \( 0.55 mg \)
c. \( 9.1 \times 10^{-24} g \)
d. \( 1.008 mg \)
