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The time taken by the stone to reach the water level is, t= sqrt(2h/g), where h= Hight of the well, g= Acceleration due to gravity. So the time taken by the sound wave to travel the distance, which is the hight of the well is t’=(2.05-t). Now t=2 sec. Hence t’=0.5 sec.

Now the velocity of the sound wave will be, v= h/t’ =392 m/s.

For the first leg of the journey, V = 0 + α t1So V = α t1

for the second leg of journey of duration t - t1 :0 = V - β (t - t1)0 = α t1 - β t + β t1

t1 = β t / (α + β)

V = αt1 = α β t / (α + β )

Let ‘t1’ be the time for which it accelerates, ‘v’ be the velocity after this time. Now, when the acceleration is α.

v = 0 + αt1

=> v = αt1

=> t1= v/α

Then it decelerates at rate β and stops at t2.

So,

0 = v – βt2

=> v = βt2

=> t2= v/β

Now, t = t1+ t2= [v/α] + [v/β] = v[(α+β)/αβ]

=> v = t[αβ/(α+β)]

Now,

Distance travelled in time t1is found as,

v2= 02+ 2αS1

=> S1= v2/(2α)

Distance travelled in time t1is found as,

02= v2- 2βS2

=> S2= v2/(2β)

Total distance travelled is,

S = S1+ S2

=> S = v2/(2α) + v2/(2β)

=> S = [v2/2][1/α + 1/β]

=> S = [v2/2] [(α+β)/αβ]

=> S = ½ [t[αβ/(α+β)]]2[(α+β)/αβ]

=> S = ½ t[αβ/(α+β)]

what is the correct option from them?

The answer is Option C.

thanks

Pollution is when smoke and chemical are introduce into the environment in large doses that make it harmful for all living things

Thanks for the answer

Acid rain is form of pollution

It's ok.

Pollution is the effects by different agents which results in the damage of environment. Pollutants can be classified according to their nature and decomposition levels. On the Basis of Nature

Depending upon the nature of the pollutants and their interaction with environment process, the pollution caused by different agents can be classified into the following categories:

1) Pollution Caused by Solid Wastes:The solid wastes includes the pollutants like garbage, rubbish, ashes, large wastes formed due to demolition and construction processes, dead animals wastes, agricultural wastes, etc.

2) Pollution Caused by Liquid Wastes:Oxygen cycle is nicely operated in aquatic system maintaining ecological balance. That is, the dissolved oxygen is used by aquatic living organisms for their respiration and in return, these liberate carbon dioxide. Carbon dioxide molecules are again used by green plants and algae in the process of photosynthesis. During photosynthesis, oxygen is again liberated to water which remains in dissolved state.On the Basis of Decomposition

1) Non-Degradable Pollutants:These are not broken down by the natural processes like action of microbes. Most of these pollutants get accumulated in the environment and also get biologically magnified as these moves along the food chains in an under-composed state. These may also react with other compounds in the environment to produce toxins. These can be further sub-divided into two more classes:

i) Waste: e.g., glass, plastic, phenolics, aluminium cans, etc.

ii) Poisons: e.g., radio-active substances, pesticides, smog gases, heavy metals like mercury, lead and their salts.

2) Degradable Pollutants or Bio-degradable Pollutants:These are natural organic substances which can be decomposed, removed or consumed and thus, reduced to acceptable levels either by natural processes like biological or microbial action or by some engineered systems, like sewage treatment plants

Current through 3 ohm = 0.8 A

Since potential drop in parallel are same.

Hence

0.8 * 3 = i * 6

i = 0.4 A

Hence current in 6 ohm resistor = 0.4 A

Now current in 4 ohm = 0.8 + 0.4 = 1.2 A

Hence potential drop across 4 ohm = 4 * 1.2 = 4.8 Volts

Chlorofluorocarbons(CFCs), once described as "miracle chemicals," cause the breakdown of the ozone layer that protects the earth from the sun's ultraviolet (UV) radiation

The UV-inducedbreakdownreleases free, highly reactive chlorine and bromine atoms from the CFCs

CFCs are now recognized as harmful chemicals because of their ozone-depleting properties

Volume will be base*height=250*2=500m^3

The electrical potential energy stored in the capacitor is = C V² /2

This energy is dissipated in the circuit through the resistance wire. That heat is absorbed by the insulated block. Apply conservation of energy :

Heat absorbed = m sΔT = C V² /2 => V = √[2 m sΔT /C]

The value of acceleration due to gravity of the earth g = 9.8 m/s²

Mass of man= mmass of boy= 1/2 mspeeds= v1 and v2KE of man= 1/2 mv1²KE of boy= 1/2 (m/2)v2²comparing both equtions1/2mv1²= 1/2 (m/2)v2²v1²= 1/4v2²

new speed = (v1+1)New KE:1/2 m(v1+1) = 1/2 (m/1)v2²(v1+1)²= 1/2 v2²

By putting the values in both equations we get:v1= 2.41m/sv2= 4.82 m/s

A chemical compound that changes color and structure when exposed to certain conditions and is therefore useful for chemical tests. Litmus, for example, is anindicatorthat becomes red in the presence of acids and blue in the presence of bases.

In physics, power is the rate of doing work or of transferring heat, i.e. the amount of energy transferred or converted per unit time. Having no direction, it is a scalar quantity.

12/(10+r) = 1.1

So, 11+1.1r = 12

1.1 r = 1

Therefore, internal resistance r = 1/1.1 =0.90909 ohms

Carbon dioxide is a waste product of respirationand in the lungs it passes out of the blood and is breathed out. Respirationis achemicalprocess when glucose or other sugars react with oxygen to produce energy. It produces carbon dioxide and water as waste products

Mangetic field B due to a current carrying conductor at a distance d from it is given by = Mu I / 2π d I = current Mu = permeability in the medium (vacuum)

Suppose P is to the left of Q. Midpoint is at d = 5/2 m = 2.5 m

If we take the wire P, direction of B due to P at midpoint between wires is upwards on the plane of paper. I assume that the current is coming out of plane of paper. Its strength is

B = 4 π * 10^-7 * 2.5 / 2 * π * 2.5 = 2 * 10^-7 Tesla, upwards

If we take the wire Q, direction of B due to Q will be downwards on the plane of paper.

B = 4 π * 10^-7 * 5 / 2 * π * 2.5 = 4 * 10^-7 Tesla, downwards

Resultant Magnetic field is : 4 * 10^-7 downwards

a)Due to the force exerted by the magnet within its magnetic field the iron fillings get attracted and arrange themselves in a particular pattern which is given by the magnetic lines of bar magnet.

b)Crowding of iron filings at the ends of the magnet indicates that the magnetic field is strongest near the poles of the magnet.

c)The lines along which the iron fillings arrange themselves represent magnetic field lines of the bar magnet.

e) Properties of magnetic field are as follows:1. They seek the path of least resistance between opposite magnetic poles.2. They flow from the south pole to the north pole within a material and north pole to south pole in air.

miror and water ☺😊😀😁

If the refractive indices are same in both medias then there will be no refraction and light will pass without any refraction.And when the incident ray is striking perpendicular to one media to another the light will pass without any refraction.

workisdonewhen the object moves through a certain distance in a particular direction after the force had been applied on it. Forwork to be done, the force must be applied and must not be zero.

R = V / II = V/RI = (25 + 25j)/(75 - 50j) = 25(1 + j) /25(3 - 2j) = (1+j)/(3 - 2j)

For n pulse rectifierRms Value varies according to the applied pulsesa relation of pulse with the rms value can be I(rms) = Id/√n

Pink is the color of phenolphthalein

Insulin regulates the blood sugar level.Adrenalineis carried in the bloodstream and controlsfunctionssuch as the heart rate, dilation of the pupils, and secretion of sweat and saliva.

have u got science paper

Regulation is given byspeed at open load- speed at full load/ speed at full load

The molecules of air and other fine particles in the atmosphere have smaller size than the wavelength of visible light. These are more effective in scattering light of shorter wavelengths at the blue end than light of longer wavelengths at the red end. The red light has a wavelength about 1.8 times greater than blue light. Thus, when sunlight passes through the atmosphere, the fine particles in air scatter the blue colour (shorter wavelengths) more strongly than red. The scattered blue light enters our eyes.

A clear cloudless day-timeskyisbluebecause molecules in the air scatterbluelight from the sun more than they scatter red light. When we look towards the sun at sunset, we see red and orangecoloursbecause thebluelight has been scattered out and away from the line of sight