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Let subscript 1 denote solid (hot body)and subscript 2 denote water (cold body)Initial temp. of solid T₁=150°CMass of solid m₁ = 50 g = 0.05 KgInitial temp. of water T₂=11°CMass of water m₂= 100 g = 0.1 KgFinal temp of both T= 20°CSpecific heat capacity of water c₂=4.2 J/g°CLet Specific heat capacity of solid be c₁now,heat gained by water = heat lost by solidheat gained/lost = mcΔT∴ m₁c₁ΔT₁ = m₂c₂ΔT₂⇒ 0.05*c₁*(150-20) = 0.1*4.2*(20-11)⇒ 0.05*130*c₁ = 0.1*4.2*9⇒ c₁ = 0.5815 J/g°CAnswer: Specific heat capacity of the solid is 0.5815 J/g°C

Total amount of heat = 8400 + 33600 + 2100 = 44100J.

Time taken = 73.5min = 4410s.

Average rate of heat extraction (power).

P = E/t = 44100/4410 = 10W

40m is the max height

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is it correct

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yes

The heat engine can convert internal energy of sea water if there is a sink at temperature lower than temperature of sea water. Since there is no such sink and hence a ship can not use the internal energy of sea water to operate the engine.

For using the internal energy of sea water to operate the engine of a ship, the internal energy of the sea water has to be converted into mechanical energy. Since whole of the interned energy cannot be converted into mechanical energy, a part has to be rejected to a colder body (sink). Since, no such body is available, so the interned energy of the sea water cannot be used to operate the engine of the ship.

54°c is the resulting temperature

as we can apply the equation as..ms(84-T)+ms(24+T)=2msT84-msT+24ms+msT=2 mst84+24=2..hence resultant temp.is 54°c

ms(84-T) +ms(24+T) =2msT84+24=2TT=108/2T=54

by applying the equation of heat we get let final temp be tms(84-t)+ms(24+t)=2mstms{84-t+24+t)=2mst108= 2t108/2=t54= tfinal temperature will 54°

1/r=1/R1+1/R2 1/r=1/6+1/31/r=1/2r=2r=8 in total v=i×rv=2×8=16v16/4=4v

Sincel,Tanddare same for the two strings, hence

v1/v2=r2/r1=2/1

Thus, the correct option is (2).

Theretinais alight-sensitivelayer at the back of theeyethat covers about 65 percent of its interior surface.

Photosensitivecellscalled rods and cones in theretinaconvert incidentlightenergy into signals that are carried to the brain by theoptic nerve.

14)Range of Vision is 25cm for normal human eye.

15The iris opens and closes tocontrolthe amount oflightentering theeyethrough the pupil. The pupil is the opening in the center of the iris wherelightenters theeye. When looking at theeye, the pupil appears black. ... The lens provides about 30 percent of theeye'stotal focusing power.

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We can see a non-luminous object when light is reflected from the object towards our eye .Option (b) is correct.

Can you remind me the formula....... Starting part that v is inversely proprtional to root r

something different Eddy current loss is less so you save the energy

Amagnetic coreis a piece ofmagnetic materialwith a highmagnetic permeabilityused to confine and guidemagnetic fieldsin electrical,electromechanicaland magnetic devices such aselectromagnets,transformers,electric motors,generators,inductors, magneticrecording heads, and magnetic assemblies. It is made offerromagneticmetal such as iron, orferrimagneticcompounds such asferrites. The high permeability, relative to the surrounding air, causes themagnetic field linesto be concentrated in the core material. The magnetic field is often created by a current-carrying coil of wire around the core.

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mass of the bullet (m) = 10 g = (10/1000) kg =0.01 kgInitial velocity (u) = 150 m/sFinal velocity (v) = 0 m/sTime taken (t) = 0.03 seci. Calculation of the distance of penetrationof the bullet into the block:Calculation of the distance of penetrationof the bullet into the block = DisplacementDisplacement = average velocity × timeDisplacement = [(u + v) / 2] × timeDisplacement = [(150 + 0) / 2] × 0.03Displacement = 2.25 mii. Calculation ofthe magnitude of the force exerted by the wooden block on the bullet:the magnitude of the force exerted by the wooden block on the bullet = Retarding forceRetarding force = mass × reatardationRetarding force = mass ×[ (Intitial velocity - Final velocity) / t ]Retarding force = 0.01 ×[ (150 - 0) / 0.03 ] NRetarding force = [150/3] NRetarding force = 50 N

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power is inversely proportional to focal lengthhence lesser focal length means more powerhence lens A

Thefocal lengthof the average, healthy, adulthuman eyeat near-pointis about 18.5 mm. Young individuals can accommodate theirlensesfurther to afocal lengthof around 15.4 mm. Thefocal length of the human eyeis thedistancebetween thelensand the retina when an object is infocus

Thefocal lengthof the average, healthy, adult humaneyeat near-point is about 18.5 mm. Young individuals can accommodate theirlensesfurther to afocal lengthof around 15.4 mm. Thefocal lengthof the humaneyeis thedistancebetween thelensand the retina when an object is infocus

(a)eye lens-thelenschanges the focal distance of the eye. In other words, it focuses the light rays that pass through it (and onto the retina) in order to create clear images of objects that are positioned at various distances. It also works together with the cornea to refract, or bend, light

(b)pupil-pupils are smaller in bright light and bigger in low light,behind the pupil,the eye has a lens

The area under velocity-time curve gives the displacement (or distance) of the moving object.

i) Distance travelled in 0 to 20s = area of triangle AOC =0.5*20*5 m = 50 m

ii) Distance travelled in 20 to 50s = area of rectangle ABDC + area of triangle BDE =20*5 + 0.5*20*10 =100+100 =200 m

well...The answer is 25×10^5 kg

thanks...

distance of near point for normal eye is 25 cm

Hypermetropia is a condition of the eye where the person is not able to see things clearly when nearer to the eye. The normal near point of the eye is 25 cm , i.e. for normal individuals to see clearly, an object must be at a distance of atleast 25 cm. For a hypermetropic eye with a near point of 1m (100 cm), to see an object placed at 25 cm, the virtual image needs to be for med at 100 cm. Hence applying the formula,

1/focal length (f)= 1/ object distance (u) + 1/ image distance (v)

Since the image formed is virtual a - (minus) sign is assigned

Hence it becomes,

1/f = 1/u -1/v

which in this situation is,

1/f = 1/25 -1/100

1/f = 4/100 - 1/100 = 3/100

Hence f = 100/3 = 33.3 cm

Diopteric power of the eye P = 100 / f = 100/ 33.3= 3 D

Hence the answer is 3D

Second half of the questions can u please solve that

In all conductors, charges reside on the surface.

The reason for this is that conductors have free electrons, that is, the electrons are loosely attached to the nucleus of the atoms in the conductors.

Refer to the pic below

When placed in external electric field, the electrons migrate to one side of the conductor and an electric field is created inside the conductor itself due to separation of positive and negative charges, as is evident from the pic. In case of conductors, this electric field is equal to that of the external electric field and hence neutralises the external field.

So the net field inside the conductor is zero.

a correct answer is (C) 20.3° C

u = 20 m/sv = 0s = 5 cm = 0.05 m

from 3rd equation, v² - u² = 2as⇒ 0 - (20)² = 2 × 0.05 × a⇒ 0.1 a = - 400⇒ a = - 4000 m/s²

deceleration will be - 4000 m/s

Eddy Currents are currents which circulate in conductors like swirling eddies in a stream. They are induced by changing magnetic field and flow in closed loops perpendicular to the plane of the magnetic field.

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Eddy currents (also called Foucault currents) are loops of electrical current induced within conductors by a changing magnetic field in the conductor according to Faraday's law of induction. Eddy currents flow in closed loops within conductors, in planes perpendicular to the magnetic field.

Eddy Current Principle. The eddy current method is based on the principle of generating circular electrical currents (eddy currents) in a conductive material. This is achieved by the use of a coil connected to an alternating current generator driving an alternating magneticfield(primaryfield).

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