Explore topic-wise InterviewSolutions in Current Affairs.

r has an electric ROD which gets heated up when we switch on it.for example,keep an container filled with WATER and an geyser in it half in water and half out heat the rod.After sometime we OBVERSE that water hs heated or very HOT.

re FIVE states of matter :-- SOLID -Liquid - Gas- PLASMA -  Bose-Einstein CondensateYes,plasma is a state of matter..

are commonly used for personal GROOMING or admiring oneself in which case the looking glass is sometimes still used, decoration, and architecture. MIRRORS are also used in scientific apparatus suchas telescopes and LASERS, cameras, and industrial MACHINERY etc..

opying:-in electro STATIC a paper is treated with a material consisting of zinc oxide combined with a thermoplastic resin.when that paper is kept in the xerox machine.it passes through a CORONA charging bar. Within the charging bar, the zinc oxide COATING picks up a negative electrical charge.the original document is exposed to light, which reflects off the white portions of the document. Dark portions of the document do not reflect light.Light reflected off the original document is then reflected by a series of mirrors to the treated copy paper which has been passed into this section of the machine. Light striking the copy paper removes negative charges placed by the charged bar, leaving charged SECTIONS that correspond to the absence of light, that is, the dark places on the original document. so the original document is xerosed into duplicate document. the exposed copy paper is passed through a toner bath, where positively-charged toner attaches itself to negatively-charged areas on the copy paper. When the paper is passed through a pair of rollers, the toner is pressed into the copy paper, forming a permanent positive image that corresponds to the image on the original document.hope this may help you if so plzz mark it as bst

rbon dioxide is dissolve in WATER it form CARBONIC acid.H2O + CO2 ⇒ H2CO3this ACIS is the carbonated water.

pan FULL of water and invert pyrex funnel and rest the wide mouth of the funnel  on coins. now start heating this entire setup with the help of SPLINTER. first the coin gets heated up because it is the impurity in water.and bubbles comes from the place where impurity(coin) is present.slowly the water surrounding the coin gets heated up. as the upper water exerts pressure on the lower part of water, the boiling POINT of the lower water increases and the lower water is heated to great extent.the bubbles tries to come up through narrow end of the funnel. but the narrowness of the funnel exerts more pressure on the deeper parts of the water resulting in increase of boiling point. when pressure increases on the deeper portion, the vapour present there tries to escape into atmosphere. this vapour ESCAPES with great force and carries the deeper water with it. the hot water comes out of the narrow end like a fountain. This is the principle used in working of geyser.

of GEYSER means how a geyser WORKS and WORKING on a geyser means you are doing some experiments or SEARCHING about it..

ds the molecules are closely packed .this MEANS that they have LESS space to vibrate and hit other molecules earlier .So the sound travels FASTEST in SOLIDS.

e height of the man : 1.50 m / 2 = 75 cm.See the diagram .There is a wall and the mirror is on it.  The man and the mirror are standing vertically on the floor.  The distance between them does not matter, as it is a plane mirror.The rays from the HEAD can be seen only if the mirror is positioned at the level of eyes.  The rays from the feet can be visible after reflection from the mirror at the height of h/2, where h is the height of the person.The mirror part, which is purple colored of height h/2 and positioned h/2 height above ground, is NEEDED.  This is the shortest mirror, for the person to be able to see his FULL IMAGE.

to swap or INTERCHANGE the connections at two phase conductors.That will reverse the current flow.  Then the direction of the motor will reverse as the TORQUE GENERATED will be in the opposite direction.

stion is that there are two masses m₁ and m₂  kept at a distance of r meters from each other.  Then to find the force of attraction between the two masses.Newtons' law of gravitation SAYS that Force We need to know the value of  m2 also to find the force.  Substitute the values in the GIVEN expression to find the answer. The force depends on the value of MASS of the second BODY.  If the mass m₂ = 50 kg also,  then the force = 4.16875 * 10⁻¹° Newtons.

se induction motors   produce torque by themselves.  This is because the INTERACTION of the MULTIPLE fields gives the torque on the rotor.  This is due to the multiple phases.  So they are self starting.   1. Squirrel cage motors:   a)     In Induction motors the starting current is very large for a short time duration.  This large current and the resulting voltage drops affect the devices in the ciruits.  The starting torque is reduced only 1/4th by increasing the rotor resistance, so that the current becomes 1/2.  B)    Auto-transformers /auto-starters :  A transformer is used for each phase.   At the start the switch on the transformer allows only a reduced part of the voltage to affect the rotor.   When the motor is near full speed, the auto-transformer automatically disconnects from the circuit.   Then the fulloutput voltage of the transformer is applied to the 3 phases.    c)     Star delta started method:         A two way switch is used to connect the stator winding in star  when the moror is in the starting phase..    When the motor is running at normal speed, the stator windings are  CONNECTED in delta (triangle) form.    In the star network form, only a reduced voltage is affects the rotor.  So the torque will be  1/square root(3) of the full voltage when the motor is operating.       2)  Slip-ring motors:               These motors can be started off with full input line voltage.  There is an external resistance connected on each phase to the brushes at the slop rings.  A star connected rheostat can be used for this purposes to add resistance in series with the rotor winding.  Thus the starting current in rotor and thus in the stator.       The rheostat can be automatically switched off or manually operated.  ===========================Single phase split phase  induction motor     (a).  a separate starting circuitry is needed.  This provides a rotation in the proper direction.    A single phase motor results in the rotation of rotor in any of the two directions.  So the starting circuitary causes the rotor to rotate in one direction only by providing the magnetic  field in the appropriate direction.         A second stator winding is fed with an out-of-phase current (by phase difference created by using an inductor or by a CAPACITANCE).  Thus the interaction of the two fields gives a start to the rotation.   As soon as the motor starts rotating and reaches the intended speed, the second winding is disconnected.   This is automatically achieved by a centrifugal switch or a thermistor.     (b).  A shaded pole:    A coppe wire wound around part of the pole.  Not complete pole..    The current induced in this turn (of the wire) lags behind the input current.  So there is a delayed magnetic field due to delayed current, around that part (shaded pole) of the pole face.   The interaction of the two magnetic fields causes rotor to rotate.  The rotational field energy to just start the motor is given by this shaded pole.  ===============      3. Power electronics methods:     Thyristors, MOSFET controlled thyristor, Insulated gate Bipolar transistor, BJT are used.

can be GROWN easily it does not NEED more WATER for its growth and no animals GRAZE it

the formula  for refraction through the curved surface (convex) of the lens, when the light falls on the unsilvered face of the lens.   We assume that  R = radius of CURVATURE of either surface of convex lens.  μ_g = REFRACTIVE index of the material of lens.  u = object distance.             1/V1 - 1/u1 =  (μ_g - 1) / R    --- (1)            1/v1 = (μ_g - 1) / R  -  1/u1    --- (2)      ,    using sign convention:From the above we find the image distance.The rays from the object get refracted and fall on the silvered surface of the lens.  We should treat the silvered surface as a concave mirror.  Hence, the light rays are reflected and converge at the image distance.  we may get a real inverted image.     v1 from the above calculation,  will act as the virtual object distance for the concave mirror.  We should USE the appropriate sign as per sign convention.   Then focal length of concave mirror will be equal to  R/2  where  R = radius of curvature.   so we use the formula:   1/v + 1/u  = 1/F      ------ (3)       We find v as we know  u and f. and sign convention.                  1/v2  - 1/v1  =  2/R                 1/v2  =  2 / R +  (μ_g - 1) / R  -  1/u1                   1 / v2  +  1 / u1 =  (1 + μ_g) / R      This is equivalent to a concave mirror  with a focal length :  (1 + μ_g) / R So the focal length is smaller than  R / 2.I hope it is correct, I am not sure.

ter bottle (made of glass or inextensible, HARD, brittle, breakable MATERIAL) is filled completely with water and kept in REFRIGERATOR, the temperature of water is reduced.  Usually the in the water bottle compartment the temperature could be 8 deg C or so.When water bottle is taken out of the fridge, the temperature of the bottle increases, water expands.  The volume expansion of water is more than the volume expansion of glass.  Thus water present INSIDE the bottle CREATES a high pressure or stress on the inner surface of the bottle.  The bottle is not easily expandable, so it breaks due to the pressure or stress.

of small drop of radius R = V1 = 4/3  π r³volume of the BIG drop of radius R = V = 4/3 π R³number of small drops combined to FORM the big drop = N = V / V1               N = R³ / r³Surface tension of liquid = surface energy / surface area = T               surface energy = surface tension * surface areaTotal surface energy stored in N small drops = 4 π r² * T * N           = 4π T R³ / rTotal surface energy stored in 1 big drop = 4 π R² * Tsurface Energy released during the merging process of all drops :   ΔE =  4 π T R³ /r - 4 π R² T         = 4 π R³ T [ 1/r - 1/R]           = 3 V T  [ 1/r - 1/R ]===================Here we are taking into ACCOUNT only the surface tension related energy.  We have ignored gravitational potential energy and the changes in the potential energy of the molecules when they merge.  Also the kinetic energy of the drops is not considered.

per second are thrown on the wall at right angles to it.mass = minitial velocity = - u  before HITTING the wall, towards the wallfinal velocity =  u after hitting the wall and rebounding, away from the wallChange of momentum of the ball during collision = m u - (-m u)  = 2 m u    As n balls are hitting the wall in 1 sec,  the TOTAL change of momentum of all the balls together in one second  =  2 n m u        FORCE = change of momentum per second. Force exerted by the wall on all the balls = 2 n m u  Hence the force experienced by the wall = 2 n m u, as action and reaction forces are equal and OPPOSITE in direction.

he angle at which the INCLINED PART of the MASS leans against the HORIZONTAL

tically, ACCELERATION is GIVEN by  where,.SUBSTITUTING your VALUES .

/SEC is the ANSWER

e D1 = 15 km     Speed V1 = 30 kmph      Duration T1 = 15/30 = 0.50 hrsDistance D2 = 75 km     speed V2 = 50kmph       duration T2 = 75/50 = 1.5 hrsDistance D3 = 10 km     speed V3 = 20 kmph      duration T3 = 10/20 = 0.5 hrs total      D = 100 km                                                      total  =  2 hours   average speed = V = total distance / total TIME duration                                 = 100 km / 2 hrs = 50 kmph==============We can also do this by using the formula:If you can use the formula, that is FINE. Other WISE do that in the first METHOD.

s:Let the AMOUNT of COPPER be M1 grams.         Temperature T1 = 60°Camount of WATER M2 = 1 LITRE = 1000 grams        temperature T2 = 27°C Resultant temperature of the mixture = T = 40°C

show a working ELEVATOR and bridge based on the PRINCIPLE of Hydraulics.For this,you need to use SYRINGES and plastic tubes.You can MAKE the elevator and bridge with the help of CARDBOARD.

tion of light waves (or other waves) is the bending of light rays around a very small obstacle when there is an obstruction in their path.   When a monochromatic light source is kept near an aperture (circular) or a slit of the order of 0.1 mm or so..  The distance between them may be quite short such that the waves that reach the obstacle or the aperture are spherical.  If the monochromatic light source is far from the obstacle or aperture, then the waves become almost planar at the slit or obstacle.   We keep a screen on the other side of aperture (or obstacle) not far from the aperture.  Perhaps LESS than a meter or so.  Now we observe the diffraction pattern of the light waves on the screen.   Each point on the spherical wave in the aperture acts as a secondary light source.  The secondary wave  fronts so emitted have DIFFERENT optical paths.  When the optical path difference is 1/2 of wavelength then destructive interference occurs.  So dark fringes (circular) appear on the screen.  At the center a bright circle appear due to the constructive interference of light waves.  So one can see fringe pattern of equal widths.   Fresnel NUMBER = F =   here,  a = aperture size      λ = wavelength of the monochromatic light source    D = distance of the screen from the aperture / obstacle.   When F >=  1 ,  the  Fresnel diffraction pattern can be seen on the screen.   If the distance D is very large and incident light waves are parallel wave fronts (distance between the light source and aperture/obstacle is very large), then a different type of diffraction occurs.  That is called :  Fraunhofer diffraction.  In that case,  F << 1.

of waters at TWO DIFFERENT temperatures.T1 = 40°C        T2 = 90°CM1 = ?            M2 = ?     Mixture:    M =  M1 + M2 = 40 kg          T = 50°C   T = (M1 * T1  + M2  * T2 ) / (M1 + M2)     = [ M1 * T1  + (M - M1) * T2 ] / M   50 = [ M1 * 40  + (40 - M1) * 90 ] / 40   2000 = 3600 - 50 M1        M1 = 32 Kg       M2 = 40 - 32 = 8 kg

make a LDR PROJECT. In which you have to use sensor. We see in many place that no one is their but the street Lights are glowing. In this case we can FIT sensor in ROAD so that the light GETS switched on only when a car or VEHICAL passes over it.

erate no HEAT is the ANSWER.

ve that like CHARGES (electric) do not attract each other.  This is according to the Coulomb's law of ATTRACTION or repulsion between electric charges.Let there be two like charges on two PARALLEL plates kept at a distance, then we  introduce some dielectric medium/slab like a glass which lets static electricity on it.  Then on the two surfaces of the slab static charges are accumulated.  They will be opposite in SIGN to the charges on parallel plates.  This is due to electro static induction.     Then in that case,  the two parallel plates move TOWARDS each other. But it is not due to attraction between the plates, it is due to attraction between the charges and the induced charges.In magnetism too, like poles repel each other.

tric geyser works on Joule's heating effect..BASICALLY there is a heating element in the geyser. This is USUALLY a resistor of very high resistance. When there is a FLOW of CURRENT, the element tried to obstruct the force and hence in this process, the electrical energy is converted to heat energy (This is Joule's heating effect). Now when this heating element is dipped in the water tank, water in turn gets heated up...This is just a BRIEF descrpition

mass of the DISC be M.  LET the mass of the MAN be  m1.  Let the mass of each block be  m2.    Let the radius of the disc be R.  Le the angular velocity of the disc be  ω.The moment of inertia of the disc, about the AXIS passing through its center and perpendicular to its surface.    I = Moment of inertia of the man:    0  as he SITS at the center.  So distance of the person from the axis of rotation is 0.  Moment of inertia of the two blocks =  2 * m2 * R²  The new inertia :  M R² /2 + 2  m2  R²               =  ( M/2 + 2 m2)  R²

case a object is EXPERIENCING two equal and OPPOSITE force, it won't show any displacement. The two FORCES will balance each other's effects, that is cancel each other, this WAY there won't be any displacement.

1  T1  + M2 T2 ] / (m1 + m2)     =  (30 * 30 + 50 * 50 ) / (30+50)      = 3400 / 80     = 42.5 deg CENTIGRADE

, petrol and perfume UNDERGO endothermic reactions which MEANS that the things TAKE in heat from there surroundings, MAKING the surroundings cool.

VITY:  DEFINITION is "it is equal to the resistance of a conductor of UNIT length and unit area of cross section"                  FORMULA for RESISTIVITY isρ=here R is resistance of conductorA is the area of cross sectionl is length

itational FORCE is GIVEN by Gm1×M2                                                  r²F=Gm1×m2/r²⇒G=Fr²/m1×m2G=[MLT-²] [L²]/[M2]    as force DIMENSIONAL FORMULA is M1L1T-2G=[M-1L³T-2]

is a portion of a TRANSPARENT medium bounded by two plane faces inclined to EACHOTHER at a SUITABLE angle.

ge of a projectile in two dimensions in the ABSENCE of any air resistance:  HORIZONTAL speed = u COS Ф  time of flight = 2 * u sin Ф  / g  So    R = u²/g * Sin 2Ф             = 84² / 9.81  * Sin (2 * 45° )            = 719.266 meters. actual range observed = 630 m% DECREASE = 89.266 / 719.266 * 100 = 12.41%

ors do not allow charges to pass through.  They do not conduct electric charges.  Air, vacuum, wood, cardboard, cotton,  Helium are NON conductors of electricity.  They can be charged by rubbing and static electricity is generated.When we use a material for protecting the electric charges from leaking or protecting humans or animals from electric current,  we call it as an insulator.When we describe a material or substance in terms of conductivity : we say CONDUCTOR or non-conductor.  But all non-conductors may not be used as insulators.  Like air is a non-conductor.  Perhaps we don't use it as an insulator.  We may prefer some other material to air.===Semi-conductor  is a non-conductor for LOW voltages across its terminals.  When the voltage goes higher than a threshold voltage, then it conducts electricity and in FACT, it gives out a higher current than that flows in to it.  Thus a semi-conductor  like Silicon, GERMANIUM etc.  are used in electronic gadgets and computers to control flow of current and also to amplify current or signal.

kmph = 72 * 5/18 = 20 m/sa = - 2 m /s²v = 0the EQUATION of motion in SINGLE dimension is :       V = u + a t        0 = 20 - 2 * t     t = 10 seconds.    s = u t + 1/2 a t²      = 20 * 10 - 1/2 * 2 * 10²     = 100 meters.  OR,    v² = u²  + 2 a s            s = ( 0²  - 20² ) / -2 * 2               = 100 meters

e the time is SPLIT into 2 parts. for first 4 m/s for second we can ASSUME 'x' m/s Then,          4+x/2=6         x=12-4         x= 8 m/s

hnically they MEAN the same thingbut SLIDING is voluntaryslipping is INVOLUNTARY

Rotational IThe rotational principle of inertia: In the absence of a net applied torque, the angular velocity remains unchanged.Newton Rotational IIτ = I αThis is not as general a relationship as the linear one because the moment of inertia, I, is not strictly a scalar QUANTITY. The rotational equation is limited to rotation about a single PRINCIPAL AXIS, which in simple cases is an axis of symmetry.Newton Rotational III For every applied torque, there is an equal and OPPOSITE reaction torque. (A result of Newton's 3rd law of linear motion.)hope it helped u.

re at rest but only with RESPECT to us. With respect to the Earth it is under motion.  Earth is under motion [Rotation and REVOLUTION] thus all the THINGS [LIVING and Non-Living] on Earth is under motion

ifferences are: (i) DISTANCE is the LENGTH of the actual PATH taken by a particle while DISPLACEMENT is the length of the shortest path between the initial and final position of the object.(ii) Distance is a scalar quantity while displacement is a vector quantity.(iii) Distance can never be negative but displacement can be negative.