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moving in fluids must have special SHAPES because the object on moving through the fluid experiences opposing force which is called Drag force, LIKE friction. This force depends on the body SHAPE of the object. So, to minimize this OBJECTS must have special shapes.

k will START SLIDING down. The FRICTION will act opposite to the direction in which BOOK is sliding. SEE the figure.

ss = dArea of cross section = Atime = tLet the conductivity = kThe TWO faces are at temperatures Th and Tc(Th>Tc).So the HEAT flow rate is GIVEN asHeat TRANSFERRED =Q

a LOADED TROLLEY we have to PUSH it.

n temperature of paper is very low. When we try to ignite a paper, all the heat is absorbed by the paper and when it reaches its ignition temperature, it catches fire.But when the paper is wrapped around a ALUMINIUM PIPE, aluminium being a GOOD conductor of heat, absorbs most of the heat and it takes more time for paper to reach the ignition temperature. So it doesn't catch fire easily.

omatic LIGHT it is a SINGLE COLOUR HENCE single FREQUENCY / wavelength.

the ARCHIMEDES law.The additional volume of WATER displaced by the boat when the man GETS onto it,      = 3 m * 2 m * 1 cm = 0.06 m³So  the weight of the man = weight of  0.06 m³ of water              = 0.06 m³ * 1000 kg/m³           = 60 kg

is not a star but a planet.when sun light is fall on venus it's reflect the most of light and it is near to the earth comper to other STARS so it's LOOK like star. and the angle betwwen sun- earth-venus is 47 degree so venus is can be seen just before SUNRISE or just after sunset as a BRIGHT morning or evening star. At these times, Venus is up to 15 times brighter than the brightest star.

lier MANUFACTURED mirrors were the pieces of polished stones. parabolic mirrors were described and studied in classical antiquity by the mathematician diodes in his work on burning mirrors. In china people began making mirrors with the USE of silver MERCURY amalgams as early as 500AD. In 16th century, venice, a big city formed for its GLASS making expertise, became a centre of MIRROR production using this new technique.

. is called Inflammable SUBSTANCE for EXAMPLE; LPG, PETROL, Spirit, ETC

quefied PETROLEUM GAS CNG-Compressed NATURAL Gas KJ-Kilo-Joule

uld take 80 CAL for CONVERTING I've to WATER, then 100 cal for bringing water from 1 to 100 degree & finally 540 cal for converting water at 100 degree to stream. Total 720 cal needed for 1g of ICE.

nck's constant,         p = momentum of electron,        m = mass of electron V = velocity of electron,          ν = frequency of wave of photonλ = wavelength of photon        E1 = kinetic energy of electronE2 = Kinetic energy of photon        c = speed of lightDeBroglie wavelength of electron = λ = h / p     p = m v  =>    p²  =  2 m E1      =>  p = √(2 m E1)        =>  λ = h /√(2 m E1)              E1 = h² / (2 λ² m)Photon     E2 = h ν = h c /λ            =>        λ = h c /E2    => E2 / E1 = h c / λ  * 2 λ² m / h²                     = 2 m c λ / h         ====================for exampleenergy of photon to energy of electron with the same wavelength 500 nm              =  2 * 9.11 * 10⁻³¹ * 3 * 10⁸ * 500 * 10⁻⁹ / 6.636 * 10⁻³⁴              = 0.008237================wavelength of electron :  λ = h / p  = h / m v,        v = velocity of electronsubstitute this value in the RATIO of ENERGIES.   E2 / E1 = 2 m c λ / h = 2 m c (h / m v) /  h   =>  E2 / E1  = 2 c / v

ht ray's wavelength :  380 nm  to  760 nm  for visible light (white rays). μ_film = 1.33 thickness of film = d = 320 nm θ1 = 0°  = angle of incidence at the top layer of film μ_air = 1 θ2 = angle of REFRACTION into the soap film = angle of reflection at the film-air interface.    μ_air Sin θ1  = μ_film  Sin θ2          --- (1)   There is a phase shift of 180 DEG. when light rays are reflected at the top surface of the film, as μ_air < μ_film.  There is no phase shift when rays are reflected at the  film-to-air interface.  The OPD (optical path difference) is:         2 μ_film  d  Cos θ2  = (m - 1/2) λ   for constructive interference.    --(2)   2 μ_film  d  Cos θ2  = m λ    for destructive interference.    -- (3)                   here m = an integer.  As θ1 = 0°,  θ2 = 0°.      2 * 1.33 * 320 nm  = Optical path difference OPD                   = 661.12  nm   In equations  (2) and (3),  the RHS is λ/2, λ, 3λ/2 ...  We have the range of white light wavelengths mentioned above.  661.12 = λ for red color  satisfies equation  (3).  So red color is destroyed.  661.12 = 1.5 λ for  λ = 440.7 nm satisfies equation (4),   ie., violet color is constructively added.

of SEPARATION of different CONSTITUENTS from petroleum is CALLED as refining .

Geysers  (geography / Physics)       A geyser is a water spring which discharges (erupts) water (along with dirt) turbulently (violently) now and then steam comes out steadily.  The geothermal energy and expansion of vapour at low pressures and high TEMPERATURES  causes the geysers.       The formation of geysers is a hydro-geological phenomenon under certain conditions.  They are nearby volcanoes and due to the presence of magma.    The small holes in Earth are called “surface vents”.     There are fractures, fissures, porous spaces, cavities in side Earth’s crust.  There is water available inside Earth up to the depth of about 10 km.   The rocks are very very hot there.   This system of water reservoir holding water, getting heated and coming out through the vents is called a plumbing system.  Along these vents SiO2 or geyserite is deposited and makes the vents smooth and hard.  They enable high pressure to be maintained along the vents.   After certain duration, the pressure of water inside Earth comes down, so geysers stop.  The water on the surface seeps through pores in Earth and this slowly collects back into the reservoirs of the geysers.  Thus the geyser cycle again starts.      They exist in about 1000-1500 places on Earth.   There are a lot of them in the USA, especially at Yellowstone National Park at Wyoming.  The Grand geyser in USA erupts for about 10 minutes every 12 hours.  There is a valley of Geysers in Russia in Kamchatka peninsula.  This is the major one in Euro-Asia.  In India there are some including one famous one in HARIYANA. There are around 80 in El Tatio , Chile.   There are some in Taup Volcanic zone in (North island of) New Zealand.   It is supposed to have reached 160 meters high.   In Iceland too there are famous geysers including the Great Geysir. =======================================                 Domestic Electric Heater/GeyserWorking principle (Physics)      The Joules heating effect of an electric resistance is used to heat water. Description of the heater:    We use electric geysers at homes or in clinics or shops to heat water.  It is cylindrical shaped and is mounted on walls. It has a capacity of 50 to 250 liters.  See diagram.    It consists of a water container vessel with an inlet for cold water and an outlet for hot water. The heater contains a thick (tubular) electric conductor (metallic resistance) coil element. It gets heated due to the dissipation of energy when current passes through it. The heat energy is transmitted to water through conduction and convection mechanisms. Usually the heating element is made of Nickel or chromium.     There is a mechanism to measure the temperature of water using a THERMOSTAT. It shuts off, automatically, the current supply to the heating element, when the temperature is above a preset value. This is set in the factory.  There may be LEDs or small bulbs to indicate whether the heater is switched on or off.    The water container is usually made of a MATERIAL which does not get corroded or rusted easily.  The water container is protected with insulating material and air gap so that the heat energy is retained inside the container.  The materials for the outer casings are usually stainless steel, plastic and china glass. Plastic is safer to prevent from leakages and shocks. =========================================Power and rating related INFORMATION:      The heater is usually based on AC voltage. It is given a rating : power it consumes, current it passes when the rated voltage is applied. Voltage rating V could be 220 V in countries like India and 110 V in USA. Power rating P could be 1 KW to 5 kW depending on size.       Heating Power P = V² / Resistance of heating coil.     If the water tank capacity is L liters, then rate of heating is:                = P / (L * density * specific heat )  = P / ( L * 1 * 4181) =                = P / (4181 L)  °K / sec     If we want to heat water from 20° to 50°, then it takes time T =                   T = 30 * 4181 L / P = 2000 L / P  minutes.     If people could wait for 15 minutes for L litres , then                    Power needed P = 2000 L /  L = 2 kW ==================================================Instant Heaters     We get instant heaters also. They have a small capacity (2 litres). The water is heated at a constant rate as the water flows through the geyser.  There is no storage and not much insulation provided in this type of heaters.  A heating (electric resistor) coil is used in them. The wattage could be around 2 kW.  Care must be taken as if there is not enough water, it may burn the coil.  Flow of water can be decreased or increased to have hotter or colder water.

d Plain is a Plain where it s SURFACE is Inclined at a PARTICULAR Angle one SIDE is Higher and the Other is ShorterAlso In Inclined Plane if a object is KEPT slides down due to Unbalanced Force

of both gases = V  (initial and final), as we ASSUME they are in fixed containers.number of moles of each gas = n  (assume)Initial temperature of both gases = TQuantity of heat given to each gas = QMono-atomic gas      Ratio of specific heats = γ₁ = 5/3     Molar Heat capacity at constant volume = = 3/2 R     Pressure  initial = P₁    ,    final = P₁',         Final temperature = T₁'          P₁ V = n R T ,       P₁'  V = n R T₁'      =>    P₁' / P₁ = T₁' / TDiatomic gas       ratio of specific heats = γ₂ = 7/5     Molar Heat capacity at constant volume = = 5/2 R      pressure  initial  = P₂  ,    final pressure = P₂'  ,       final temperature = T₂'         P₂ V = n R T   ,       P₂'  V = n R T₂'        =>      P₂' / P₂ = T₂' / T              ==>    P₂  =  P₁          and           P₂' / P₁'  =   T₂' / T₁'=================There is no change in volumes.  Hence the WORK done W by each gas is zero.                   Q = ΔU + W     Q = ΔU = change in internal energy = As molar heat capacity for the diatomic gas is more than that of monoatomic gas, the temperature INCREASE for the diatomic gas will be less.   Thus, the mono-atomic gas will have higher temperature.

is a transparent curved DEVICE that is used to refract light. Its usually made of GLASS.

e USED to convert SOLAR energy into ELECTRICAL energy

that retain energy after interacting with an electron via the photoelectric EFFECT are said to undergo Compton SCATTERING.  if a photon has any amount of energy greater than the applicable photoelectric work function, it can theoretically undergo Compton scattering.  visible light can Compton scatter. However, the probability of Compton scattering at these ENERGIES is very low, not to mention these scattered photons would most LIKELY loose all of their energy from all of the other various available atomic interactions before they could even escape the SAMPLE, which is a necessary component to measurement (something has to exist in order to be measured). Therefore, the effects of Compton scattering are negligible at visible light energies.light. These kinds of energies are associated with x-rays.

des principle states that when an OBJECT immersed in water,upthrust is equal to the WEIGHT of water DISPLACED by it.

ition reaction is single compound break into two or more simple SUBSTANCES under suitable conditions.calcium carbonate is decomose by heating and form calcium oxide and CARBON dioxideCaCO3 -->  CaO + CO2       displacement reaction in which a more REACTIVE element displaces a less reactive element.  zinc react with hydrochloric acid and zinc displace the hydrogen and produce zinc chloride and hydrogen gas. ZN + 2HCl -->  ZnCl₂  + H₂

ce = F        so acceleration a = F/m     a = (v - u) / t  = (4.2 - 1.8) / 1.2 = 2 m/sec²     SINCE same force is applied again, the same acceleration happens.     v = u + a t    =>    v - u = a t = 2 m/sec² * 2SEC =  4 m/sec    change in SPEED = 4 m/s2)    s = 20 meters. = displacement       v² = u² + 2 a s            -- equation of motion under gravity,  a = + g       v² = 0 + 2 g s    =  2 * 10 * 20           v = 20 m/sec  = FINAL velocity

re of the RESISTING POWER of a specified MATERIAL to the flow of an electric current. The si UNIT is ohm.Press thank you!

[rocess of CONVERSION of ghaseous STATE into LIQUID state and ALSO it should COOL down

t ) =  2  Sin πx    COS  100π t       x and y are in meters  and t is in seconds.we use the formula in trigonometry  2 Sin A Cos B = Sin (A+B)  + Sin (A-B)  y (x, t)  =  2  Sin (π x)     Cos (100 π t)                 =  Sin (πx + 100πt)    +    Sin  (πx - 100 πt)                 =  Sin (πx + 100πt)    -    Sin  (100πt  -  πx )                 =  Sin (100 πt + πx)   +  Sin  (100 πt  -  πx + π)general formula  for a standing wave :  y (x, t) = A Sin (ω t - k x + Ф)  these are the component WAVES which are part of the stationary wave.component wave 1:    y1 (x,t)  =  sin (π  x  +  100 π t)       angular frequency = ω    = 100 π  RADIANS/sec      frequency = f  = 50 Hz = ω/2π              TIME period: 1/f = 0.02 Sec.       Amplitude = A = 1 m       wave number  k =  - π  rad/meter                       we have formula   ω = k v           velocity  v =  ω / k  = - 100 meters/sec          wavelength λ =  v / f  =  100/50  meters =  2 meters  this component of the wave is traveling in the negative x direction. so its velocity is negative. ==========================component wave 2:    y1 (x,t)  =  sin ( 100 π t - π x +  π )       angular frequency = ω    = 100 π  radians/sec      frequency = f  = 50 Hz = ω/2π              Time period: 1/f = 0.02 Sec.       Amplitude = A = 1 m       wave number  k =  π  rad/meter                       we have formula   ω = k v           velocity  v =  ω / k  = 100 meters/sec          wavelength λ =  v / f  =  100/50   meters =  2 meters   initial phase angle = π radians this wave is traveling in the positive x direction.  so  k and v are positive.But the waves are have a phase difference also.

hagorean THEOREM:

s a DEVICE used to COOK FOOD utilising Solar ENERGY

velocity of a PLANET of MASS M at a DISTANCE R from its centre is given by For A, radius = 4R, velocity = 3vfor B, radius = R, velocity = ? Speed of satellite B is 6v.

l Energy of a given MASS M of a GAS (mass of each molecule = m) is given by the formula :     E = 1/2 M v² = 3/2 * R T         M = mass of  gas         v = rms velocity = root mean square velocity         R = universal gas constant         T = ABSOLUTE temperature of the gas   Energy of a molecule is given by : 1/2 m v² = 3/2 k_B T         k_B = Boltzmann's constant           m = mass of a molecule.   THUS  v = √(3 R T / M)  = √(3 k_B T/m)     For a given gas,  the rms velocity depends only on the square root of the absolute temperature of the gas.             v2/v1 = √(T2/T1) = √4 = 2        So rms velocity becomes doubled.

onvex lens;1.)Beyond 2f -           2.) diminished2.)At 2f -                  3.)same size3.)Between F and 2f - 4.)enlarged4.)At focus -             1.)INFINITIVE largeHope i HELPED u:)

the ATTACHMENT

et 6 ohm       We  connect the three resistors in SERIES.  so resistances are added to get the effective resistance:  1 + 2 + 3 = 6 Ω2)  to get  6/11 Ω       We connect all the resistances in parallel.  The effective resistance be R.             1/R = 1/1 + 1/2 + 1/3 = 11/6                  R = 6/11 Ω3)  to get  1.5 Ω         We connect  1 Ω and 2 Ω in series.  Hence, resistance of the two will be 3 Ω.  Then connect the  3 Ω resistance in  parallel with the series connection of 1 Ω and 2 Ω.               so effective resistance  =  R                   1/R =  1/(1+2)  + 1/3 = 2/3                   R = 3/2 Ω = 1.5 Ω