CBSE Class 12 Physics Atoms MCQs Set D

Question. Balmer series is obtained when electron transits from             
a) n = 1,2,3, … to n = 5
b) n = 3,4,5 … to n = 2
c) n = 1,2,3, … to n = 4
d) n = 1,2,3, … to n = 6

Answer: B

Question. From Fig. shown predict which series has waves of maximum frequency       
a) Lymen
b) Balmer
c) Paschen
d) Bracket

Answer: A

Question. If number of protons in an atom is equal to (number of electrons + 2). Then the atom is said to be   
a) Single ionized positive ion
b) Single ionized positive atom
c) Double ionized positive ion
d) Double ionized positive atom

Answer: C

Question. Which is the most dense part of an atom?   
a) The exact central part of the atom.
b) The region at the center of atom containing neutrons and protons.
c) Outer edge of the atom
d) None of the options

Answer: B

Question. What percentage of α particle scattered at an angle more than 90º?     
a) .0125%
b) .125%
c) 1.25%
d) 12.5%

Answer: A

Question. Why the nucleus of gold is about remains stationary throughout the scattering process?         
a) Because its mass is 100 times the mass of proton.
b) Because its mass is 50 times the mass of proton.
c) Because its mass is 150 times the mass of proton.
d) Because its mass is 200 times the mass of proton.

Answer: D

Question. Why electrons around the gold nucleus were unable to deflect α particles? 
a) Size of α particle is much greater than that of electron.
b) Number of electrons around gold nucleus is very small
c) α particles is much heavier than electron.
d) Electrons are negatively charged.

Answer: C

Question. What is the ratio of charge on α particle and gold nucleus?     
a) .025
b) .25
c) .2
d) .5

Answer: A

Question. What is the basic unit of matter?             
a) Atom
b) Electron
c) Proton
d) Neutron

Answer: A

Question. The series of spectrum when electron jumps from n = 5 to n = 3 is     
a) Lymen
b) Balmer
c) Paschen
d) Bracket

Answer: C

Question. What is the maximum energy of photon in emission spectrum of hydrogen atom         
a) 13.6 eV
b) 1.36 eV
c) 1.5 eV
d) 1eV

Answer: A

Question. Which particle is responsible for the ionization of the atom?       
a) Positron
b) Electron
c) Proton
d) Neutron

Answer: B