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2021-09-27 18:47:47 Notes on Breathing and Exchange of Gases

Pulmonary Volumes and Capacities
There are following respiratory volumes and capacity:

(i) Tidal volume (TV): It is volume of air normally inspired or expired in one breath (i.e. inspiration and expiration) without any extra effort. It is about 500 ml in normal healthy adult. In infants it is 15 ml and in fetus it is 0 ml.

(ii) Inspiratory reserve volume (IRV) : By taking a very deep breath, you can inspire a good deal more than 500 ml. This additional inhaled air, called IRV is about 3000 ml.

(iii) Expiratory reserve volume (ERV) : If you inhale normally & then exhale as forcibly as possible, you should be able to push out 1200 ml of air in addition to 500ml. of T.V. The extra 1200 ml is called ERV.

(iv) Residual volume (RV): Even after expiratory reserve volume is expelled, considerable air remains in the lung, this volume, which cannot be measured by spirometry, and it is called residual volume is about 1200 ml.

(v) Dead space: Portion of tracheobronchial tree where gaseous exchange does not occur is called dead space. It is also called conductive zone. Dead space is 150 ml.

(vi) Functional residual capacity (FRC): It is the amount of air that remains in the lungs after a normal expiration. It is about 2300 ml.

FRC = ERV + RV
= 1100 + 1200
= 2300 ml.

(vii) Vital capacity (VC): This is the maximum amount of air that can be expired forcefully from his lungs after first filling these with a maximum deep inspiration. It is about 4600 ml.

VC = IRV + TV + ERV
= 3000+500+1100 = 4600 ml.

(viii) Total lung capacity (TLC): TLC is the sum of vital capacity (VC) and residual volume (RV). It is about 5800ml.

TLC = VC + RV
= 4600 + 1200 = 5800 ml.

(ix) Inspiratory capacity (IC): It is the total amount of air a person can inspire by maximum distension of his lungs.
I.C. = TV + IRV
= 500 + 3000 = 3500 ml

Process of Respiration
The process of respiration is completed in 4 steps:

Breathing or ventilation

Exchange of gases or External respiration

Transport of gases

Cellular respiration

Ventilation or breathing:
Breathing is movement of thorax, expansion (inflation) and deflation of lungs and flow of air into the lungs and from the lungs. It is extracellular, energy consuming and physical process. Sum of inspiration and expiration is called respiratory movement.
There are two steps of breathing:

Inspiration: Intake of fresh air in lungs from outside. It is an active process. Blood pressure increases during later part of respiration.

Expiration: Out flow of the air from the lungs is called expiration. When expiration occurs, the inspiratory muscles relax. As the external intercostal relax, ribs move inferiorly and as the diaphragm relaxes, its dome moves superiorly owing to its elasticity. ओपन / कमेंट

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2021-09-25 16:55:57 Notes on Chemical Coordination and Regulation


Properties of hormones
(a) These are secreted by endocrine gland (biogenic in origin).

(b) Their secretions is released directly into blood (except local hormones e.g. gastrin).

(c) These are carried to distantly locate specific organs, called target organ.

(d) These have specific physiological action (excitatory or inhibatory). These co-ordinate different physical, mental and metabolic activities and maintain homeostasis.

(e) The hormones have low molecular weight e.g. ADH has a molecular weight of 600–2000 daltons.

(f) These act in very low concentration e.g. around10–10 molar.

(g) Hormones are non antigenic.

(h) These are mostly short-lived. So have a no camulative effect.

(i) Some hormones are quick acting e.g. adrenalin, while some acting slowly e.g. ostrogen of ovary.

(j) Some hormones secreted in inactive form called Prohormone e.g. Pro-insulin.

(k) Hormones are specific. They are carriers of specific information to their specific target organ. Only those target cell respond to a particular hormone for which they have receptors. ओपन / कमेंट

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2021-09-24 15:37:24 Chemical Properties of Alkali Earth Metals:



1. Reaction with water :

Mg + H2O → MgO + H2

or, Mg + 2H2O → Mg (OH)2 + H2

Ca + 2H2O → Ca(OH)2 + H2

2. Formation of oxides and nitrides

Be + O2 (air) +Δ→ 2BeO

3Be + N2 (air) +Δ → Be3N2

Mg + air + Δ → MgO + Ng3N2

3. Formation of Nitrides

3M + N2 + Δ → M3N2

Be3N2 + Δ → 3Be + N2

Ba3N2 + 6H2O + Δ → 3Ba (OH)2 + 2NH3

Ca3N2 + 6H2O + Δ → 3Ca (OH)2 + 2NH3

4. Reaction with hydrogen:

M + H2 + Δ → MH2

Both BeH2 and MgH2 are covalent compounds having polymeric structures in which H – atoms between beryllium atoms are held together by three
centre – two electron (3C - 2e) bonds as shown below:

5. Reaction with carbon – (Formation of carbides)

When BeO is heated with carbon at 2175 – 2275 K a brick red coloured carbide of the formula Be2C is formed

2BeO +2C \xrightarrow[]{2175 - 2275 K}Be_2C +2CO

It is a covalent compound and react water forming methane.

Be2C + 4H2O → 2Be (OH)2 + CH4

6. Reaction with Ammonia:

Like alkali metal, the alkaline earth metals dissolve in liquid ammonia to give deep blue black solution from which ammoniates [ M (NH3)6 ]2+ can be recovered.

Anamolous Behaviour of Beryllium:
Be is harder than other members of its group.

Be is lighter than Mg.

Its melting and boiling points are higher than those of Mg & other members.

Be does not react with water while Mg reacts with boiling water.

BeO is amphoteric while MgO is weakly basic.

Be forms covalent compounds whereas other members form ionic compounds.

Beryllium carbide reacts with water to give methane whereas carbides of other alkaline earth metals gives acetylene gas.

Be2C + 4H2O → 2Be (OH)2 + CH4

Mg2C2 + 2H2O → Mg (OH)2 + C2H2

CaC2 + 2H2O → Ca (OH)2 + C2H2

Beryllium does not exhibit coordination number more than four as it has four orbitals in the valence shell. The other members of this group has coordination number

Diagonal relationship of Be with Al:
Unlike groups – 2 elements but like aluminium, beryllium forms covalent compounds.

The hydroxides of Be, [Be(OH)2] and aluminium [Al(OH)3] are amphoteric in nature, whereas those of other elements of group – 2 are basic in nature.

The oxides of both Be and Al i.e. BeO and Al2O3 are high melting insoluble solids.

BeCl2 and AlCl3 have bridged chloride polymeric structure.

The salts of beryllium as well as aluminium are extensively hydrolysed.

Carbides of both the metal reacts with water liberating methane gas.

Be2C + 4H2O → 2Be (OH)2 + CH4

AI4C3 + 12H2O → 4Al (OH)3 + 3CH4

The oxides and hydroxides of both Be and Al are amphoteric and dissolve in sodium hydroxide as well as in hydrochloric acid.
BeO + 2HCI → BeCI2 + H2O

BeO + 2NaOH → Na2BeO2 + H2O

Al2O3 + 6HCI → 2AICI3 + H2O

AI2O3 + 2NaOH → 2NaAIO2 + H2O

Like Al, Be is not readily attacked by acids because of the presence of an oxide film.
Calcium Carbonate (CaCO3):
It occurs in nature as marble, limestone, chalk, coral, calcite, etc. It is prepared as a white powder, known as precipitated chalk, by dissolving marble or limestone in hydrochloric acid and removing iron and aluminium present by precipitating with NH3, and then adding ammonium carbonate to the solution; the precipitate is filtered, washed and dried.

CaCl2 + (NH4)2CO3 →CaCO3 + 2NH4Cl
It dissolves in water containing CO2, forming Ca(HCO3)2 but is precipitated from solution by boiling.

CaCO3 + H2O + CO2 Ca(HCO3)2 ओपन / कमेंट

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2021-09-22 16:13:29 Notes on Wave Optics

Huygens Principle:- Wave-front of a wave, at any instant , is defined as the locus of all the particles in the medium which are being disturbed at the same instant of time and are in the same phase of vibration.

(a) Each point on a wave front acts as a source of new disturbance and emits its own set of spherical waves called secondary wavelets. The secondary wavelets travel in all directions with the velocity of light so long as they move in the same medium.

(b) The envelope or the locus of these wavelets in the forward direction gives the position of new wave front at any subsequent time.

Determination of Phase Difference:-
The phase difference between two waves at a point will depend upon

(a) The difference in path lengths of the two waves from their respective sources.
(b) The refractive index of the medium
(c) Initial phase difference between the source if any.
(d) Reflections, if any, in the path followed by waves.

Reflection of plane wave at plane surface (Laws of reflection):-

a) The incident ray, the reflected ray and normal to the reflecting surface at the point of incidence, all lie in one plane and that plane is perpendicular to the reflecting surface.
b) The angle of incidence is equal to the angle of reflection.

So, ∠i = ∠r

This signifies angle of incidence is equal to the angle of reflection.

Refraction of light:-
Refraction is the phenomena by virtue of which a wave going from one medium to another undergoes a change in velocity.

(a) The sine of the angle between the incident ray and the normal bears a constant ratio to the sine of the angle between refracted ray and the normal.

sin i/sin r = v1/v2 = 1µ2 = constant

Here, v1 and v2 are the velocities of sound in first and second medium respectively.1µ2 is the refractive index of the second medium with respect to first.

(b) The incident ray, the refracted ray and the normal to the refracting surface lie in the same plane.

Interference:- The modification in the distribution of light energy obtained by the superposition of two or more waves is called interference.

Principle of superposition:- It states that a number of waves travelling, simultaneously, in a medium behave independent of each other and the net displacement of the particle, at any instant, is equal to the sum of the individual displacements due to all the waves.

Displacement equation:- y = R sin 2π/λ (vt+x/2)

Amplitude:- R = 2a cos πx/λ

Intensity:- I = K4a2 cos2 (πx/λ) [I = KR2]

Maxima:- A point having maximum intensity is called maxima.

x = 2n (λ/2)

A point will be a maxima if the two waves reaching there have a path difference of even multiple of λ/2.

Imax = 4Ka2 = 4i (Here, i = Ka2)

Minima:- A point having minimum intensity is called a minima.
x = (2n+1) (λ/2)

A point will be a minima if the two waves reaching there have a path difference of odd multiple of λ/2.

Imin = K. 4a2×0 = 0

Condition for constructive interference:-
Path difference = (2n)λ/2

Phase difference = (2n)π

Condition for destructive interference:-
Path difference = (2n+1)λ/2

Phase difference = (2n+1)π

Coherent Sources:- Coherent sources are the sources which either have no phase difference or have a constant difference of phase between them.
Conditions for interference:-
(a) The two sources should emit, continuously, waves of same wavelength or frequency.

(b) The amplitudes of the two waves should be either or nearly equal

(c) The two sources should be narrow.

(d) The sources should be close to each other.

(e) The two sources should be coherent one.

Young’s double slit experiment:-
Path difference, x = yd/D

Maxima, y = nλD/d

Here, n = 0,1,2,3….

Minima, y = (2n+1) λD/d

Here, n = 0,1,2,3….

Fringe Width:- It is the distance between two consecutive bright and dark fringes.
β = λD/d

Displacement of fringes due to the introduction of a thin transparent medium:-
(a) Shift for a particular order of fringes:-

?y = (β/λ) (µ-1)t

(b) Shift across a particular point of observation:-

µ = (mλ/t) +1

Lloyd’s single mirror:-
?λ = β .2a/D

Power of lens:- P = 100/f ओपन / कमेंट

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2021-09-21 07:28:25 @jeemainguru
━━━━━━━━━━━━━━━━━━━━
QUICK REVISION
FORMULAS

1. Formulas related to force:
F = ma
F = kx
F = m(vf² - vi²/2S)
F = mv/t
F = md/t²
F = m(vf - vi)/t
F = Area × density × velocity²
F = 1/2 mv²/d
F = 1/2 Pv/d
F = Power/velocity
Fc = mv²/r
Fc = mrw²
Fc/2 = mv²/2r
Fc = 2K.E/r
F = Area × Stress
F = pir² × stress
F = YA × Strain
F = YAl/L
F = pressure × area
F = change in momentum × time interval
F = - 2mVx × Vx/2l
F2 = F1/A1 × A2
F = qE
F = kQ/r²
F = ILB sintheta
F = q (v × B)
F = qE + q(v × B)

2. Formulas related to energy and work
Fd = k.e
mgh = 1/2 mv²
E = 1/2 kx²
E = Ve
E = nhf
E = nhc/lambda
E = Pc
K.e = hf - work function = hf - hf° = hf - hc/w° (here w° is cutt off wavelength)
E = 1/2 Pv
mv²/2r= Fc/2
K.E/r = Fc/2
K.E = Fc×/r/2
K.e = 1.5 KT
E = VQ
E = Power × time
E = Fvt
% loss in K.e = v1² - v2²/v1² × 100
% loss in P.e = h1² - h²/h1² × 100
Energy lost due to air friction(Fh) = 1/2mv² - mgh (when body is thrown upward)
Energy lost due to air friction(FS) = mgh - 1/2mv² (when body is thrown downward)
E = 1/2 CV² (capacitor)
E = R × hc (R is Rydberg' constant)
J = m-¹ × Js ms-¹
hf kalpha x rays = EL - Ek
hf kbeta x rays = EM - Ek
Binding energy = mass defect × c²
W = Fd Costheta
W = nmgh (when person is climbing stairs)
W = n(m+m) gh (when person is climbing stairs with some load)
W = 0mgh + 1mgh + 2mgh + 3mgh ....... (in case of stacking bricks. For ist brick h=0. For 2nd brick h=1. For 3rd brick h=2 and so on)
W = Fd = PA × change in V
W = Q - change in U
Q = mc × change in T
T/273.16 = Q/Q3 (Thermodynamic scale)
W = I²Rt
W = emf×charge
W = VQ
W = 1/2 lF
W = YAl²/2L
W = StressAl²/2Strain
W = PressureAl²/2Strain
W = Fl²/2Strain

3. Formulas related to Power
P = Fv
P = E/t
P = n(mgh/t)
P = Fd/t
P = mv²/2t

4. Formulas related to distance, displacement, velocity and accelration
d = vt
d = at²
d = (vf + vi/2) ×t
d = 5t² (for distance in 'n' seconds)
d = 5(2tn - 1) (for distance in 'nth' second)
d = 1/2 mv²/F
d = vit + 5t²
d = v × underroot 2H/g
d = vt = x°wt = x°2pi/T × t = x°2pift
x = x° Sin wt
x = x° Sin (underroot k/m) t
vf = vi + at
2as = vf² - vi²
2as = (vi + at)² - vi²
2as = vf² - (vf - at) ²
v = underroot Vfx² + Vfy²
v = Power/Force
v = 2×K.E/momentum (k.e = 1/2 Pv)
v² = 2×Power×time/mass (P = mv²/2t)
v = underroot 2as
v = underroot gr (speed at highest point in a verticle circle)
v = underroot 5gr (speed at lowest point in a verticle circle)
v² = 2FS/m
v² = 2E/m
v² = 2Ve/m
v = eBr/m (velocity of particle under action of magnetic force along circular path)
v² = Force/Area.Density
v = w underroot x°² - x²
v = underroot k/m × underroot x°² - x²
v = x°w (at mean position where x=0)
v = x° underoot k/m
v = v° underroot 1 - x²/x°² (for determining ratio b/w inst. Velocity and maxi. Velocity)
v= x°2pif = x°2pi/T
a = x°w² = x°w.w = vw = v.2pif
Common velocity = m1v1/m1+m2
vi² = Rg/Sin2theta
v = underoot Tension×length/mass
V = 2pi ke²/nh (speed of e- in nth orbit)
Vn = V/n
v = nh/2pimr (lambda = 2pir and lambda=h/p)
ma = kx
a = kx/m (SHM)
a = - gx/l (Simple pendulum)
ac = v²/r

5. Formulas related to wavelength 'w'
w = v/f
w = 1/wave number
w1 = 2l (when pipe is opened at both ends)
w1 = 4l (when pipe is opened at one end)
Delta w = Us/f (doppler shift)
Wavelength for obs. = w - delta w = v/f - Us/f
w = hc/Ve
w = hc/E
w = h/mv
w = h/P as P = underroot 2mE so
w = h/underroot 2mE (de Broglie wavelength)
w = underroot 150/V A° (short method for de Broglie wavelength. This formula is applicable only for e-)
1/w = RH (1/p²-1/n²)
Wmaxi/Wmini = n²/n²-p² (for determining ratio b/w maxi. Wavelength to mini. Wavelength for series of atomic spectrum)
w = 2pir/n (n is no. of loops in a circle ओपन / कमेंट