Chemistry Class 9th

161. Atoms of particular elements are --------

A) Identical

B) Not identical

C) Changed

162. -Rutherford performed experiment in

A) 1919

B) 1914

C) 1911

163.- Rutherford used ------- foil in his experiment

A) Aluminum

B) Silver

C) Gold

164. He bombard gold foil with ------ particles

A) Alpha

B) Beta

C) Both a and b

165-The radioactive source used in experiment was

A) Uranium

B) Polonium

C) Xenon

166- α- particles are ---------- charged

A) Positively

B) Negatively

C) Neutral

167. Positively charged central part of atom is called 16

A) Electron

B) Nucleus

C) Protons

168. Nucleus is responsible for ------ of atom

A) Mass

B) Energy

C) Both a and b

169. This modal based on laws of

A) Motion

B) Gravitation

C) Both A and B

170- Boher presented atomic theory in -------

A) 1910

B) 1912

C) 1913

171-Electrons revolve around nucleus in circular paths , called

A) Orbit

B) Shell

C) Both a and b

172. The energy of electron in an orbit is depend on

A) Distance of electron from nucleus

B) Type of nucleus

C) No. of electrons

173- Energy of an orbit is ------

A) Fixed

B) Not fixed

C) Vary

174- The energy will be ------ when electron goes from lower energy level to higher

A) Release

B) Absorb

C) No change

175- The energy difference between two levels is given by

A) E= hf

B) E = hυ

C) Both a and b

176- In E = hυ the h is called

A) Plank’s constant

B) Boher’s constant

C) Both a and b

177- The value of h=

A) 6.02× 10 23 Js

B) 6.22× 10 38 Js

C) 6.324× 10 34Js

178- In formula E= hf the f represents

A) Frequency

B) Time

C) Momentum

179- Angular momentum of an electron is integral multiple of

A) mvr

B) h/2π

C) hf

180- Mass of electron in amu is

A) 0.000548597

B) 0.00554432 

C) 0.05456