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Thelaw of reflection statesthat the incident ray, thereflectedray, and the normal to the surface of the mirror all lie in the same plane.

Furthermore, the angle ofreflectionis equal to the angle of incidence . Both angles are measured with respect to the normal to the mirror.

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copper .

copper it's right answer OK...

copper is the right answer.

copper is the right answer

copper is correct answer of following question

copper is correct answer

(2) copper is right ans

copper is the correct answer

2) copper is the correct answer

speed of the river water is 4km/h

let the velocity of the river be x. the velocity of the river will be in the horizontal direction

velocity of boat in still water is 5km/hr. As the width of the river is 1 km and time taken by the boat to cross the river along the shortest path is 15 min therefore the velocity of the boat is= 1*60/15= 4km/hr

according to the figure the velocity of the river is along AB . By applying triangle law of vector addition the value of AB comes to be 3km/hr

Advantage of Mendeleev Periodic Table :

1.He left blank places which help scientist to discover new element

2.When Noble gasses was discovered Hel could add it to periodic table without any major change

3.He predicted the property of new element

After double differentiating the given equation we get the acceleration ,i.e d²x/dt²=A(w²)×-sin(wt) =-(w²)×Asin(wt)But we know that Asin(wt) =x,Therefore, answer is a=-w²x

given

x = 5t2+ 18t

we know that

v = dx/dt = d/dt[5t2+ 18t]

or

v = 10t + 18

now, the instantaneous velocity at t = 2s is given as

v = 10x2 + 18

or

v = 38 m/s

now,

at t = 2s

x1= 5(2)2+ 18(2) = 56m

and at t = 3s

x2= 5(3)2+ 18(3) =99m

so,

total distance travelled

dx = (x2- x1)

total time taken

dt = 1s

so, average velocity

vav= dx/dt = (99 - 56) / 1

thus,

vav=43 m/s

dv / dt = 10a = 10 m/ s

9)An ecosystem is a community made up of living organisms and nonliving components such as air, water, and mineral soil.

v= dx/dt= 8-8*t at t=1 you get v=0 and the particle stops and reverses direction split the integral of v into two region 0<=t<=1 and 1<t<=2 and later add them together and get the solution

x1= 8*t-4*t^2 ....8*1-4*1^2= 4 m x2 = [0-(8-4)] = 4 m x=x1+x2 = 8 m

why we did integration of v

A concave mirror forms a virtual image of a real object.

(b) is correct option

the answer is( b) it must be aconcave mirror

C Is the correct answer

A convex mirror always forms virtual image. A concave mirror produces virtual image when it is placed too closely to it.A plane mirror always forms virtual image.Therefore option (c)is the correct answer

At initial position both A and B are at rest, hence momentum is zero. It is given that no external force is acting on them .So, momentum remains zero. Since mass cannot be zero, therefore velocity is zero

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option B can be correct . Although plane mirror always forms virtual image of real object.

image can help you.. that when the incident ray is comvergent in nature.. then real image can be formed.

Initially both A and B were at rest. So momentum of centre of mass is 0. And it is given that there is no external force. Hence no change in momentum of centre of mass. And it will remain 0. As momentum(product of mass and velocity) is zero ans mass is not zero, velocity must be 0.

u know the perimeter of circle is 2pi r.here r is radius ________________________

now

Point A all P,Q,R particle present ,

now point B is present on opposite side of A

________________________________P particle goes from A to B anticlockwise ,

so it travel 2pi*10/2=10pi_________________________________Q particle goes clockwise ,

similarly to P is also be 2pi*10/2=10pi_____________________

and R particle goes through the centre that why the distance travel by the R is 10+10=20(because 10 is the radius of circle)

__________________________________

now ratio of P/Q=10pi/10pi=1

P/R=Q/R=10pi/20=pi/2

yes, option a is the correct answer

but correct answer should be option B

otherwise all the options a,c, d should be correct they also come below the visible range

The total of the electric flux out of a closed surface is equal to the charge enclosed divided by the permittivity.

The electric flux through an area isdefinedas the electric field multiplied by the area of the surface projected in a plane perpendicular to the field.

Given,Initial velocity, u=12m/sFinal velocity, v=8m/stime,. t= 5 slet deceleration be aWe know, the first equation of motion is v=u+at =>8=12+a*5 =>-4=5a =>a=-4/5 m/s^2= -0.8 m/s^2So deceleration is 0.8m/s^2

λ = 4/1097 × 10^4 = 0.003646 × 10^-4 = 3.646 × 10^-7 m

Let the force be F,Mass is M,time for which it is accelerated = 2svelocity is increased from 3m/s to 7m/sso, acceleration is , a = (7-3)/2 = 2m/s²The force applied is, F = ma = (5)(2) = 10 NNow, the force is applied for 5s, the velocity after 5s will be,v=u+at=> v =3+(2)(5)=>v=13m/s , this is final velocity.

In this Journey, the train has accelerated and decelerated motion.

For accelerated motion :Initial velocity=u=0m/sacceleration=a=2m/s2time=t=half minute=30 secFinal velocity =V=?From first equation of motion , v=u+atv=0+2x30=60m/sSo train has travelled 60m/s before brakes are appplied.

Hence the maximum speed attained by train 60m/s.

Distance travelled : From second equation of motion : S=ut+1/2at²S=0x30+1/2 x 2x 30²s=900m/ss=900/1000 =0.9km

c) The position of train at half the maximum speed [30m/s]:=Let s be the position of train at half the maximum speedv²-u²=2ass=v²-u²/2as=30²-0²/2x2s=900/4=225m

For decelerated motion :Final Velocity=V=o m/sinitial velocity=u=60m/stime=60secFrom first equation of motion : v=u+at0=60+ax60a=-60/60=-1m/s2

Distance travelled during this part is :s=ut+1/2at²=60x60+1/2 (-1x60²)=3600-1800=1800m=1.8km

Hence total distance travelled by train=0.9km+1.8km=2.7km

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dw=(3t²-2t+1)dt=>w=[t³-t²+t](2s to 4s)so W=56-12+2=46 J.It is the kinetic energy

3 is the right answer

dE = TdsT = surface tension , ds change in area =(0.05)2(0.2) = 2*10-3joules

The potential energy at height of 10m =mgh =m×10×10 =100m(jule)

On sticking the ground,the potential energy get converted into kinetic energy

Kinetic energy=100J

Energy is reduced by 40%

so the remaining energy=60%×100 =60J

The height upto which the ball can bounce back is given by 'h' such that mgh=60m×10×h=60×mh=60/10h=6m

thanks

25 cm is the least distance

this is not the answer

Control of Magnet Strength

One of the most important features of an electromagnet is the ability to change its magnetic force. When no electric current flows through the magnet’s wires, it has no magnetic force. Put a little current in the magnet, and it has a small force. A large current gives the magnet a bigger force, able to lift or pull heavier objects. The ability to turn magnetic force on and off has many important uses, ranging from simple household gadgets to giant industrial machines.

Greater Magnet Power

The pulling power of a permanent magnet is limited to the type of metal from which it’s made. Currently, the strongest permanent magnets are made of a combination of iron and a metal called neodymium. Although these permanent magnets are strong, the best electromagnets are more than 20 times stronger.

Work done by the heart will be given by, W = P.∆ VHere, P is the pressure and ∆ V is the volume of blood being pumped.Now, pressure P = hρgWhere, h = height of mercury column = 130 mm = 0.13 mρ = density of mercury = 13.6 g/cm3 = 13.6 × 103 kg/m3And, g = acceleration due to gravity = 9.8 m/s2Also, ∆ V = 4000 l = 4 × 10–3 m3Where, t = 60 sUsing these values in the equation of power, we get P = 1.15 WThus, the power of heart is 1.15 watt ~ 1.2watt

1 watt= 0.00134 british horsepower

why is the colour of the blood red

the volume of the body =v cm³andthedensityof the body = d gcm⁻³.

Theweight of the body in air,Wair= vdgdyne, where g is the acceleration due to gravity.

The buoyant force on the body when it is completely immersed is the weight of displaced water,Wbouyant =v x 1 x gdyne.

The weight of the body in water, Wwater = Wair - Wbuoyant = vg(d−1)dyne

According to the question, Wwater =1/3Wair

⇒vg(d−1) =1/3vdg

⇒d−1 =1/3d

⇒d−d/3= 1

⇒2d/3= 1

⇒d=3/2= 1.5 gcm⁻³.

14)A moving object will never stop if there is nofriction. Actually it isimportantbecause it basically allows us to do everyday things: driving a car, picking up objects etc. Without it everything would just slip and slide, with nothing to grip onto. ...Friction"pushes" the wheels in a circular motion.

Helpful frictionPeople often usefrictionto slow things down. These brake blocks usefrictionto slow the bike wheels. When the skydiver opens the parachute, air resistance slows him down. ...Frictionalso wears engine parts, so they need replacing.

15)Elastic collision is a collision where the colliding objects bounce back without undergoing any deformation or heat generation. Inelastic collision is a collision where the colliding objects are distorted and heat is generated.2. In elastic collision, the momentum and total kinetic energy before and after collision is the same.3. In inelastic collision, the energy changes into other energies such as sound energy or thermal energy.4. The forces during elastic collision are conservative and the mechanical energy is not transformed into some other form of energy such as sound energy or thermal energy.5. The Forces during inelastic collision are non-conservative and mechanical energy is transformed into some other form of energy such as sound energy or thermal energy.6. An example of elastic collision is the movement of the swinging balls. An example of inelastic collision is an automobile collision.

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It is found that the stable nuclei have binding energy per nucleon between 8 and8.8 MeV

Theairinside a tire which is about toburstis at very high temperature and pressure. Now,whenthe tirebursts airrushesoutand there is a sudden decrease inairpressure and temperature. This is what causes theairto become cooler as the pressure is reduced which causes temperature of theairto reduce as well.

The kinetic energy of wind was traditionally used to do mechanical work like pulling water from a well or lifting. Nowadays, we can generate electricity using windmills.The potential energy of stored water at a height and the kinetic energy of flowing water were traditionally used to do mechanical energy. Nowadays, hydroelectric power stations are built to make use of the energy of water to generate electricity.