Home Courses Contact About




1. (JEE Main 2024 (Online) 29th January Evening Shift)

Given below are two statements:

Statement I : Most of the mass of the atom and all its positive charge are concentrated in a tiny nucleus and the electrons revolve around it, is Rutherford's model.

Statement II : An atom is a spherical cloud of positive charges with electrons embedded in it, is a special case of Rutherford's model.

In the light of the above statements, choose the most appropriate from the options given below

A.Both Statement I and Statement II are true

B.Statement I is true but Statement II is false

C.Statement I is false but Statement II is true

D.Both statement I and statement II are falseStatement I is false but Statement II is true Statement I is false but Statement II is true

Correct answer option is (B)

According to Rutherford atomic model, most of mass of atom and all its positive charge is concentrated in tiny nucleus & electron revolve around it.

According to Thomson atomic model, atom is spherical cloud of positive charge with electron embedded in it.

Hence, Statement I is true but statement II false.

   

2.(JEE Main 2024 (Online) 8th April Morning Shift)

In an alpha particle scattering experiment distance of closest approach for the α particle is 4.5 × 10 − 14   m . If target nucleus has atomic number 80 , then maximum velocity of α -particle is __________ × 10 5   m / s approximately.

( 1 4 π ϵ 0 = 9 × 10 9 SI unit, mass of α particle = 6.72 × 10 − 27   kg )

Correct answer is 156

1 2 m v 0 2 = 1 4 π ϵ 0 z ( e ) r 1 2 × 6.72 × 10 − 27 v 0 2 = 9 × 10 9 × 80 × 2 × 1.6 × 1.6 × 10 − 19 × 10 − 19 4.5 × 10 − 14 v 0 2 = 2 × 9 × 80 × 1.6 × 1.6 × 2 6.72 × 4.5 × 10 − 38 + 14 + 27 + 9 v 0 2 = 243.8 × 10 12 v 0 = 15.6 × 10 6 v 0 = 156 × 10 5