NCERT Physics 12th

As per the NCERT Textbooks

“An integrated Chip consists of many passive and active components fabricated on a single chip of silicon. these ICs are compact, low-cost, and highly reliable. They consume less power and have high speed.”

These ICs are used in majority of our daily use electronics and all advance electronics. 

 A p-type semiconductor is electrically neutral despite having more holes, because the number of positively charged holes is exactly balanced/equal by the number of negatively charged acceptor ions introduced during doping. so practically untill any volatage is applied the semiconductor remains chargeless in other words doesn't produce any current even after doping.

 As per the NCERT Textbooks information"Although the number of holes is more than the number of electrons in a p-type semiconductor, the material as a whole is electrically neutral because the charge of holes is balanced by the negatively charged acceptor ions.”

As per NCERT Textbboks"If forward current is too large, it can produce large heating and damage the junction. So, a resistor is used in series with the diode to limit the current in the circuit.”

It means when a semiconductor diode is connected to a source under high current it causes excess heat due to more electrical energy. This excess heat is responsible to damage the junction in semiconductor diode permanently. Student can check out NCERT Solutions for Semicondutor Electronics of class 12 physics.  

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

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

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

Force of repulsion between two spheres

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

(b) Charge on sphere A, $q_A$ = 2 $*$6.5  $*{10}^{-7}$C = 1.3

Charge on sphere B, $q_B$ = 2 $*$ 6.5 $*{10}^{-7}$C = 1.3

Distance between the spheres, r =
$\frac{50}{2}$ = 25 cm = 0.25 m

Force of repulsion between two spheres

F =  $\frac{1}{4\pi {?}_0}$ $*\frac{q_1{q}_2}{r^2}$, where ${?}_0$ = Permittivity of free space = 8.854  $*{10}^{-12}$ $C^2{N}^{-1}$$m^{-2}$Therefore, F = 
 $\frac{1}{4*\pi *{8.854\mathrm{}*{10}^{-12}}_{}}$ $*\frac{1.3\mathrm{}*{10}^{-6}*1.3\mathrm{}*{10}^{-6}}{{0.25}^2}$N = 0.243 N

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 raisins or plums, also known as “plum pudding model.”