Ncert Solutions Physics Class 12th

1.13 When the third uncharged sphere C is brought in contact with the sphere A, then the charge is shared and becomes half. Then

 $q_A$ = $\frac{q}{2}$and  = $q_C$= $\frac{q}{2}$

When the charged sphere C is brought in contact with charged sphere B, the charge between both the sphere is shared and becomes half

 $q_B,q_C=\frac{1}{2}$ (q +&

1.12 (a) Charge on sphere A, $q_A$ = 6.5 $\times {10}^{-7}$ C

Charge on sphere B, $q_B$ = 6.5$\times {10}^{-7}$ C

Distance between the spheres, r = 50 cm = 0.5 m

Force of repulsion between two spheres

F = $\frac{1}{4\pi {?}_0}$ $\times \frac{q_1{q}_2}{r^2}$ , where ${?}_0$= Permittivity of free space = 8.854$\times {10}^{-12}$ 
  $C^2{N}^{-1}$$m^{-2}$Therefore, F =  $\frac{1}{4\times \pi \times {8.854\mathrm{}\times {10}^{-12}}_{}}$ $\times \frac{6.5\mathrm{}\times {10}^{-7}\times 6.5\mathrm{}\times {10}^{-7}}{{0.5}^2}$N = 0.0152 N = 1.52  $\times {10}^{-2}$N

(b) Cha

Ans.1.12

(a) Charge on sphere A, $q_A$ = 6.5 $\times {10}^{-7}$ C

Charge on sphere B, $q_B$ = 6.5$\times {10}^{-7}$ C

Distance between the spheres, r = 50 cm = 0.5 m

Force of repulsion between two spheres

F = $\frac{1}{4?{?}_0}$ $\times \frac{q_1{q}_2}{r^2}$ , where ${?}_0$= Permittivity of free space = 8.854$\times {10}^{-12}$ 
  $C^2{N}^{-1}$$m^{-2}$Therefore, F =  $\frac{1}{4\times ?\times {8.854\mathrm{}\times {10}^{-12}}_{}}$ $\times \frac{6.5\mathrm{}\times {10}^{-7}\times 6.5\mathrm{}\times {10}^{-7}}{{0.5}^2}$N = 0.0152 N = 1.52  $\times {10}^{-2}$N

(b) Charge on

1.11

(a) When polythene rubbed against wool, a number of electrons get transferred from wool to polythene. Hence, wool becomes positively charged and polythene negatively charged.

Amount of charge on the polythene piece, q = -3 $*{10}^{-7}$ C.

Amount of charge of 1 electron e = -1.6 $*10-19$

So number of e

The principle of mass-energy equivalence, given by Einstein's equation:

$E = mc^2$It states that mass and energy are interchangeable.

A small amount of mass can be converted into a large amount of energy because the speed of light $(c = 3 \times 10^8 \, \text {m/s})$ is very large and appears squared in the equation.

Significance in Nucl

Nuclear Binding Energy is the amount of energy required to completely dismantle a nucleus into its individual protons and neutrons which is equivalent to the amount of energy to form a nucleous from its constituent nucleons (protons and neutrons).

Binding energy is calculated using Einstein's mass-en

As per the NCERT Textbooks, Thomson proposed a Atomic Structure of Atom that tells" An atom consists of a positively charged sphere in which the electrons are embedded like the seeds are embedded in watermelon. This model is often compared to a pudding or watermelon with electrons distributed like r

The presesnt day theory for structure of Atom is developed through many discoveries and hypothesises. In class 12 Physics, Atom chapter includes development of the sturucture of atom, and theories in the path of development of present theory. Students can check the ordered points below;

1. Thomson's Mod

Students who are preparing for the class 12 board exams needs additional practice questions after completing the NCERT Exercises. We have provided practice questions with accurate and atep-by-step solutions for students to better prepare for the board exams. Students can check the below provided lin