# Atoms-CBSE Class 12th NCERT Solution

Get detailed solutions to the questions of the chapter atoms from NCERT physics textbooks

Get detailed solutions to the questions of the chapter atoms from NCERT textbooks. The objective is to helping students regarding the pattern of answering the question as per the cbse latest marking scheme.Cbse.jagranjosh.com provided you NCERT solutions for classes 12th math and science subjects.

Some questions of this chapter are given here.

Q. Suppose you are given a chance to repeat the alpha-particle scattering experiment using a thin sheet of solid hydrogen in place of the gold foil. (Hydrogen is a solid at temperatures below 14 K.) What results do you expect?

Sol.
There would be no large-angle scattering, because the alpha-particle has mass nearly four times than that of the target nuclei. No observable conclusion can be made in this solid hydrogen alpha-particle scattering experiment.

Q. A difference of 2.3 eV separates two energy levels in an atom. What is the frequency of radiation emitted when the atom make a transition from the upper level to the lower level?

Sol.
Given:
E = 2.3 eV
We know
v = E / h
Substitution produces
v = 5.55 x 1014 Hz

Q. Choose the correct alternative from the clues given at the end of the each statement:
a)The size of the atom in Thomson’s model is .......... the atomic size in Rutherford’s model. (much greater than/no different from/much less than.)
b)In the ground state of .......... electrons are in stable equilibrium, while in .......... electrons always experience a net force. (Thomson’s model/ Rutherford’s   model.)
c)A classical atom based on .......... is doomed to collapse. (Thomson’s model/ Rutherford’s model.)
d)An atom has a nearly continuous mass distribution in a ..........but has a highly non-uniform mass distribution in ..........(Thomson’s model/ Rutherford’s model.)
e)The positively charged part of the atom possesses most of the mass in .......... (Rutherford’s model/both the models.)

Sol.
a)No different from
b)Thomson’s model; Rutherford’s model
c)Rutherford’s model
d)Thomson’s model; Rutherford’s model
e)Both the models