NEET EXAM PDF

2021-08-04 16:40:28 Physics pro tip -
Guys Improve your reading skills. It is one of the things most of us neglect these days. Let me tell how it will help you in saving time. You see many of us don't understand the question in 1 time and read it 2-3 times and say reading 1 time takes approx 10 seconds. then you take 30 seconds just reading it many times. Now getting back to reading. If you guys read any kind of text whether subject related or not for atleast 10-15 minutes everyday your reading skills will increase.Try to read difficult and newer type of texts.
what will happen?
- You will be able to read faster than ever.
-You will be able to understand the abstract of the questions pretty easily in less time.
now how will it help you ?
say you take 10 seconds to read an average sized / big sized question
and say from 45 questions you read 20 questions 3 times.
now how much extra time you took ?
20x (2x10) = 400 seconds = 6.67 minutes and you all know importance of each minute so here if you have good reading habits you can save your 4-5 minutes atleast.
this can help you solve more questions in less time , hope it will help you , try reading texts.

All the best

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2021-08-02 19:33:56 Notes on Atomic Physics


e/m of an electron (Thomson Method):-

(a) e/m of a particle is called the specific charge of the particle.

e/m = v/rB

Here, r is the radius of curvature, B is the strength of magnetic field, v is the velocity, e is the charge on cathode ray particle and m is the mass.

(b) v = E/B

Electric field:- E = V/d

Photo electric effect:- Photo-electric effect is the phenomenon of emission of electrons from the surfaces of certain substances, mainly metals, when light of shorter wavelength is incident upon them.

Effect of collector’s potential on photoelectric current:-

(a) Presence of current for zero value potential indicates that the electrons are ejected from the surface of emitter with some energy.

(b) A gradual change in the number of electrons reaching the collector due to change in its potential indicates that the electrons are ejected with a variety of velocities.

(c) Current is reduced to zero for some negative potential of collector indicating that there is some upper limit to the energy of electrons emitted.

(d) Current depends upon the intensity of incident light.

(e) Stopping potential is independent of the intensity of light.

Effect of intensity of light:- The photoelectric currentis directly proportional to theintensity of incident radiation.

Effect of frequency of light:-

(a) Stopping potentialdepends upon thefrequency of light. Greater the frequency of light greater is the stopping potential.

(b) Saturation current is independent of frequency.

(c) Threshold frequency is the minimum frequency, that capable of producing photoelectric effect.

Laws of Photoelectricity:-

(a) Photoelectric effect is an instantaneous process.

(b) Photoelectric current is directly proportional to the intensity of incident light and is independent of its frequency.

(c) The stopping potential and hence the maximum velocity of the electrons depends upon the frequency of incident light and is independent of its frequency.

(d) The emission of electrons stops below a certain minimum frequency known as threshold frequency.

Energy contained in bundle or packet:-

E = hf = hc/λ

Here h is the Planck’s constant and f is the frequency.

Work function:- It is defined as the minimum energy required to pull an electron out from the surface of metal. It is denoted by W0.

Einstein’s equation of photoelectric effect:-

(a) ½ mvmax2 = hf – W0

(b) ½ mvmax2 = hf – hf0 = h(f- f0) = h [c/λ – c/λ0]

(c) eV0 = hf - W0

(d)V0 = [(h/e)f] – [W0/e]

Here f0 is threshold frequency.

Threshold frequency (f0):- f0 = work function/h = W/h

Maximum kinetic energy of emitted photo electrons:-

?Kmax= ½ mvmax2 = eV0

Threshold wavelength:- λ0 = c/f0 = hc/hf0 = hc/W

Slope of V0~ v graph:- Slope= h/e

Rest mass of photon = 0, Charge = 0

Energy of photon:- E = hf = hc/λ

Momentum of photon:- p = E/c = h/λ = hf/c

Mass od photon:- m = E/c2 = h/cλ = hf/c2

For electron, λe = [12.27/√V]Å

For proton, λp = [0.286/√V]Å

For alpha particle, λα = [0.286/√V]Å

For particle at temperature T, λ = h/√3mKT (E = 3/2 KT)

The wavelength of electron accelerated by potential difference of V volts is:-

λe= [12.27/√V]Å

Number of photons:-

(a) Number of photons per sec per m2, np = Intensity/hf

(b) Number of photons incident per second, np = Power/hf

(c) Number of electrons emitted per second = (efficiency per surface)× (number of photons incident per second)

Compton wave length:-
(a) λc = h/m0c

Here h is the Planck’s constant, m0 is the rest mass of electron and c is the speed of light.

(b) Change in wavelength:- λ' – λ =λc (1-cos?)

de Broglie wavelength (λ):-λ = h/mv = h/√(2mE) = h/√(2meV)
In accordance to Bohr’s postulate of atomic structure, the angular momentum of an electron is an integral multiple of h/2π.

So, mvr = nh/2π

Bragg’s diffraction law:- 2dsinθ = nλ

Here λ is the wavelength of electron and d is distance between the planes.

Rutherford’s atomic model (α-particle scattering):-
(a) N(θ) ∝ cosec4(θ/2)

(b) Impact parameter, b = [(Ze2) (cot θ/2)]/[(4πε0)E]
Here, E = ½ mv2 = KE of theα particle.
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2021-08-01 16:10:02 Tricks to remember first 30 elements in periodic table
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2021-07-28 20:14:53 Increasings or Decreasing Order

01. Melting point=
Li > Na > K > Rb > Cs

02. Colour of the flame=
Li-Red, Na-Golden, K-Violet, Rb-Red, Cs-Blue, Ca-Brick red, Sr-Blood red, Ba-Apple green

03. Stability of hydrides =
LiH > NaH > KH > RbH> CsH

04. Basic nature of hydroxides=
LIOH < NaOH < KOH < RbOH < CsOH

05. Hydration energy=
Li> Na > K> Rb > Cs

06.) Reducing character=
Li > Cs > Rb > K > Na

07. Stability of +3 oxidation state=
B> Al > Ga > In > T1

08. Stability of +1 oxidation state= Ga < In < TI

09. Basic nature of the oxides and hydroxides=
B< Al< Ga < In < TI

10. Relative strength of Lewis acid= BF3 < BCl3 < BBr3 < BI3

11. Ionisation energy=
B> Al In
12. Reactivity=
C
13. Metallic character=
C< Si < Ge < Sn < Pb

14. Acidic character of the oxides=
Co2 > SiO2 > Ge02 > SnO2 > PbO2

15. Reducing nature of hydrides=
CH4 < SiH4 < GeH4 < SnH4 < PbH4

16. Thermal stability of tetrahalides=
CCl4> SiCl4> GeCl4> SnCl4 > PbCl4

17. Oxidising character of M+4 species=
GeCl4 < SnCl4 < PbCl4

18. Ease of hydrolysis of tetrahalides=
SiCl4 < GeCl4 < SnCl4 < PbCI4

19. Acidic strength of trioxides=
N203 > P2O3 > As2O3

20. Acidic strength of pentoxides=
N2O2 > P2O2> As202 > Sb2O2 > Bi̟202

21. Acidic strength of oxides of nitrogen=
N2O < NO
22. Basic nature/ bond angle/ thermal stability and dipole moment of hydrides=
NH3 > PH3 > AsH3 > SbH3 > BiH3

23. Stability of trihalides of nitrogen=
NF3 > NCl3 > NBr3

24.Lewis base strength=
NF3
25. Ease of hydrolysis of trichlorides=
NCl3 > PCI3 > AsCl3 > SbCl3 > BiCl3

26. Lewis acid strength of trihalides of P, As, and Sb=
PCl3 > ASCl3 > SbCl3

27. Lewis acid strength among phosphorus trihalides
PF3 > PCl3 > PBr3 > PI3

28. Melting and boiling point of hydrides=
H2O > H2Te > H2Se >H2S

29. Volatility of hydrides=
H2O < H2Te < H2Se < H2S

30. Reducing nature of hydrides=
H2S < H2Se < H2Te

31. Covalent character of hydrides=
H2O < H2S < H2Se < H2Te

32. The acidic character of oxides (elements in the same oxidation state)=
SO2 > SeO2 > TeO2 > PoO2
SO3 > SeO3 > TeO3

33. Acidic character of oxide of a particular element (e.g. S)=
SO < SO2 < SO3
SO2 > TeO2 > SeO2 > PoO2

34. Bond energy of halogens=
Cl2 > Br2 > F2 > I2

35. Solubility of halogen in water =
F2 > Cl2 > Br2 > I2

36. Oxidising power=
F2 > Cl2 > Br2 > I2

37. Enthalpy of hydration of X ion=
F- > Cl- > Br- >I-

38. Reactivity of halogens:=
F> Cl> Br > I

39. Ionic character of M-X bond in halides
= M-F > M-Cl > MBr > M-I

40. Reducing character of X ion:=
I- > Br- > Cl- > F-

41. Acidic strength of halogen acids=
HI > HBr > HCI > HF

42. Reducing property of hydrogen halides
= HF < HCL < HBr < HI

43. Oxidising power of oxides of chlorine
= Cl2O > ClO2 > Cl206 > Cl2O7

44. Decreasing ionic size=
02- > F- > Na+ > Mg2+

45. Increasing acidic property=
Na2O3 < MgO < ZnO< P205

46. Increasing bond length=
N2 <02 < F2 < CL2

47. Increasing size=
Ca2+ < Cl- < S2-

48. Increasing acid strength=
HClO < HClO2 < HClO3 < HClO4

49. Increasing oxidation number of iodine=
HI< I2
50. Increasing thermal stability=
HOCl < HOClO < HOClO2 < HOClO3
»»--☆-

Important term
1: Anti Histamine = Use in Allergy
2: Analgesic = Pain Killer
3: Anti Pyretic = Fever
4: Anti Septic = Pus
5: Anti Biotic = Infection
6: Anti Anaemia = Low blood
7: Anti Emetic = Vomting
8: Anti Acid = Stomach Burn
9: Anti Flantulents = Gases
10: Anti Spasmodic = Abdominal pain
11: Anti Anginal = Cardiac pain
12: Anti Arhthnic = Cardiac Activity
13: Ant Hypertensive = BP
14: Anti Lipemic = Cholesterol+Lipids
15: Anti Coagulant = Norrowing of Blood
16: Anti Depressant = Depression

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2021-03-10 08:45:47 Trick for complete periodic table
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2021-03-10 08:45:38 Tricks to remember first 30 elements in periodic table
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2021-03-10 08:45:33 Aliphatic Amines
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