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Final ANSWER : 12° 

Steps:
1) We know,

LENGTH of tube, L = 2 dm 
Concenntration ,C = 0.1 g/mL 

Now, 


Hence, Plane of POLARIZED light is rotated by +12° .

In order to understand the significance of back EMF, let us see what happens if there is no back EMF.

Let’s make up an example of a fictitious DC motor that has permanent magnets (i.e. fixed strength field).

Let’s say a VOLTAGE of 12 V is applied to the motor. The armature winding has a resistance of 0.2 Ohms (neglecting other resistances in the path e.g. brush contacts).

If there is no back EMF, the armature willdraw a current of 60 A and produce a heating of 720 Watts in just the (I^2)R loss. Outrageous ! Right ?

However, as the armature’s current interacts with the field winding’s magnetic field, the armature experiences the torque, and it starts moving. The movement induces a voltage in the armature winding that opposes the external voltage. This opposing voltage is what we call the back EMF. The back EMF is PROPORTIONAL to field, and it is also proportional to the angular speed of the armature.

Now, the external voltage drops across the armature due to the sum of the back EMF and the armature I-R drop.

Vs - Vb = Ia * Ra

Where

Vs is supply voltage,

Vb is back EMF,

Ra is resistance of armature winding, and

Ia is the armature current

In practice, the resistance of the armature is SMALL enough that the IR drop (at reasonable currents) is a very small fraction of the external voltage.

Thus, Vs = Vb (approximately)

That is, in practical terms, the back EMF almost balances out the external voltage.

At the start, the armature is not moving, and the back EMF is ZERO. The armature current is very high. The torque is the product of the field and the armature current. The initial torque is high. As the armature moves, the back EMF appears, and grows higher. The armature current drops gradually. The torque drops gradually, and the speed approaches the stead STATE speed.

Thus, the back EMF plays two roles

It limits the currentIt plays a self-regulating role on speed and helps run the motor at a close to constant speed (a small percentage of variation) from no LOAD to full load.

Due to back EMF, you can take an ideal voltage source, and a near-ZERO resistance armature winding, and the motor would still limit itself to a finite speed, current, and torque. That would not be possible without back EMF.

Hope this helps.

The phase diference between any two points situated on the same WAVEFRONT is zero.

First of all, what is WAVEFRONT ?

• Wavefront is a term extensively used in study of wave optics.

• Now, wavefront is defined as the locus of all those vibrating PARTICLES of a wave oscillating in the same phase.

• As the definition states , all the particles in a wavefront have the same phase and HENCE the phase difference between them will be zero.

• Wavefront is usually found placed perpendicular to the direction of propagation of the wave.

Lets discuss about a few wavefronts :

• For a point source we get to SEE spherical wavefronts at various radii.

• For a line source we get to see cylindrical wavefronts at various radii.

• For sources placed at INFINITY we get plane wavefronts at various distances.

Hope It Helps.

The RELATIVE density of a substance is DEFINED as the ratio of the density of that substance to the density of water at 4oC. It is also defined as the ratio of the mass of substance to the mass of EQUAL volume of water at 4oC. i.e., R.D. = Mass of the substance / mass of an equal volume of water at 4oC.

Work done=force *displacement

so MASS is given.

so force= mass *g

force= 5* 10

force= 50N

now,

work done =force *displacement

work done= 50 * 2

work done =100 J

hope it HELPS:)

The 2D TRANSLATION equation is P'=P+T. 6 Translation is arigid BODY transformation that moves OBJECTS without deformation.

No. of UNKNOWN INTERNAL FORCE is 3.
Hope it HELP U

Teleportation is the theoretical transfer of matter or energy from one point to another without traversing the physical space between them. Teleportation, or the ability to TRANSPORT a PERSON or object instantly from one PLACE to another, is a technology that could change the course of CIVILIZATION and alter the destiny of nations.
Since 1993, energy and particle teleportation has become a HOT topic in quantum mechanics.

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What are the carbon compounds we COME across in our daily life?

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T-NEZ | CERTIFIED EDUCATOR

Nearly all of the compounds that you encounter in your daily life contain carbon. The most notable exceptions are water and oxygen. Here are some examples of carbon-containing compounds:
1. The food you eat contains carbon in the form of carbohydrates, protein, fat and fiber.
2. The clothes you wear contain carbon in both natural fibers like wool and cotton and synthetic fibers like polyester.
3. The vehicle that you use for transportation contains carbon in steel and in plastics and polymers, and the fossil FUELS such as gasoline and diesel that power the vehicle.
4. Natural gas used to heat BUILDINGS and cook food contains carbon.
5. In some parts of the country electrical power is produced by burning coal, a form of carbon.
6. The plastics and polymers used in consumer products such as PHONES, laptops and furniture contains carbon.
7. The wood used in buildings, furniture and consumer products contains carbon.
8. The asphalt used to SURFACE the roads that you travel contains carbon. 
9. The paper in the books you read and that you use for writing contains carbon. 
10. If you use any medications they most likely contain carbon.
 

E.F. of a CHARGED PARTICLE INSIDE a charged CONDUCTOR is ZERO.

Where is MOF in the FIG

Its very simple. A fan rotating with CONSTANT angular velocity, an object moving back and forth about a MEAN position periodically with constant speed, EARTH revolving around the sun, a perfectly ELASTIC basket ball bouncing on a perfectly rigid surface, etc. are allexamples of NON harmonic periodic motions.

If the ENERGY of a ball falling from a height of 10 meters is reduced by 40%, how high would it rebound?

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7 ANSWERS



Mudasir Hanif Shaikh

Answered Jul 21, 2017

Let E be the energy of the ball falling through a height of 10m

E = mgh (potential energy) 
E = m(9.8)(10)
E = 98m J ; (where m = mass of body.)

now let’s suppose the body losses 40% of its energy and REBOUNDS BACK to a height of “h1’and its new energy is “E1” which is 60% of the initial energy “E”

E1 = 60% (E)

also

E1 = mgh1 (the mass remains the same)

=> m(9.8)h1 = 60/100 ( 98m)

the m’s cancel out.

Therefore, 
9.8 (h1) = 0.6 (98)
h1 = 0.6 (10)
h1 = 6m.

Let US consider an electron and a photon of the same de BROGLIE wavelength λ

Total Energy

Let the electron have a relativistic mass m

Then its momentum =mv = h/ λ, so m= h/ λv… (1)

Momentum of the photon is also h/ λ, so its effective mass mγ =h/λc…(2)

Since V mγ

Since, E (the total energy) =Relativistic mass* c2, it follows that the total energy of the electron is greater than that of the photon, both having the same wavelength.

Kinetic Energy (KE)

In the case of the photon, all its energy is kinetic, which is ch/ λ. This can also be WRITTEN as p2/ =mγ, where E= KE = pc

For the electron, KE = p2/2M

Thus KE (photon)/KE (electron) =2m/ mγ =2c/v (from (1) and (2), which is >1 (since c>v))

Therefore, KE of the photon (which is also the total energy of the photon) is greater than the kinetic energy of the electron, both having the same wavelength.

Hey mate... ✌✌✌
here is ur ANSWER... ⤵⤵⤵⤵✴

optical fibres .....⤵⤵

a long thin thread of GLASS through which information, SOUND, data, ETC. can be sent in the FORM of light

hope it's help u ✳✳✴♥☑☑

This SEQUENCE of who EATS what is called the FOOD chain. This is a process through which the energy is transferred from one organism to the other through food. So, technically anything which we eat to LIVE is called food. This food gives us the energy to run, play and LEARN.

⛦Hᴇʀᴇ Is Yoᴜʀ Aɴsᴡᴇʀ⚑
▬▬▬▬▬▬▬▬▬▬▬▬☟

▶0ptons "B".
=============⤵

➧ Since, the focal length of the spherical mirror and the thin spherical LENSE is NEGATIVE then it means a virtual image is formed on reflection.

➧ One characteristics of IMAGES formed on convex mirrors is that they are virtual.

So, they are both convex.

_________
Thanks...✊

In YELLOW LIGHT a SWAN will APPEAR of yellow in COLOUR.

1. Dams interfere with natural flora and fauna of river system.
2. Dams CREATE atmosphere for breeding of mosquitoes.
3. Dams prevent fish migration.
4. Dams destroy ecology and environment during construction which is irreversible.
5. In hilly REGIONS hills become fragile and keep sliding for years after.
6. Debris obtained during construction somehow flows back into the dam from dumping sites.
7. Its failure can be catastrophic.
8. Downstream farmers are disadvantaged.
Marine life suffers.
9. But they have their inherrant ADVANTAGES in controlling floods, providing cheapest HYDRO power.

The room would get WARMER! ... If you LEAVE the door open, heat is merely recycled from the room into the refrigerator, then BACK into the room. A net room TEMPERATURE increase would result from the heat of the motor that would be constantly RUNNING to move energy around in a circle.

A SCALAR quantity is a ONE dimensional measurement of a quantity, like temperature, or mass.  A vector has more than one number ASSOCIATED with it.   A simple EXAMPLE is VELOCITY.

The degree of induced magnetism depends on the nature of the magnetic material.
The degree of induced magnetism is directly proportional to the STRENGTH of the inducing MAGNET being USED, and INVERSELY proportional to the distance between the inducing magnet and the magnetic material.AS a reason for all these properties the magnetic induction has an ability to PRECEDES magnetic attraction. 

A CLINICAL thermometer is used in a human body
we can say that when a PERSON is ill so to MEASURE the body TEMPERATURE we can use clinical thermometer

# Solution-

Assuming that the MASSES of the two metals are the same as are all other conditions like temperature, pressure except the specific heat, the METAL with the higher specific heat would PRODUCE the greater burn.

# Reason-

The metal with the greater specific heat TRANSFERS more heat energy as it cools down over a given temperature range. That is it will cool more SLOWLY than the other metal under the same conditions.

Strain=0.06/100

Young's MODULUS (Y)=2×10^10

It is given that,
mass of CYLINDER, m = 5kg
radius of cylinder , r = 30CM = 0.3 m
ANGULAR IMPULSE , ∆L = 3kgm²/s

here, initial angular speed is
angular speed after 4s =

we know,
angular impulse = change in angular momentum
3 =
Here I is moment of inertia.
3 =1/2 mr²( -0)
6 = 5 × (0.3)² ×
= 40/3 rad/s

now, use
40/3 = 0 + × 4
= 10/3 rad/s

now angular speed after 30 sec = 0 + 10/3 × 30
= 300/3 = 100 rad/s

I THINK POTENTIAL and if potential is WRONG then it is KINECTIC

Causes Of Air Pollution :-
1)tremendous increase in number of automobiles.
2)industries development.
3)cutting trees in large numbers.
4)burning of fossil fuels .

Effects Of Air Pollution :-
On Human Beings:-
1)itching in eyes and other eye related problems.
2)respiratory disorders LIKE ASTHMA.
On Environment :-
1)global warming:- increase in temperature.
2)unpredictable change in weather.
3)ozone layer depletion.
4)forest fire.
On Plants:-
1)decreases photosynthesis rate in plants.
2)covers the stomata due to the deposition of a thick layer of DUST on the surface of leave.
3)affects the growth of plants.

Controlling MEASURES Of Pollution :-
1)use of catalytic converter in automobiles.
2)use electrolytic purifier in industries over chimneys.
3)afforestation
4)use of public vehicle and adopting car pooling.
5)LIMITED use of fossil fuels and should avoid as possible.
6)use of CNG in automobiles and LPG in cylinders in houses.

Hope It Helps You :). :) :)

• An AC generator can be converted into DC Generator either by rectifier or by step to step replacement of certain components in the AC generator.

• It can BEGIN by replacing two brushes present in AC generator with four DIFFERENT brushes. The slip rings used in the AC generator can be removed and SPLIT rings can be replaced instead.

• Now, AC generator uses concave magnets, change them and lastly remove the COIL and replace it with armature instead. The AC generator will start functioning as a DC generator.

He is suffering from HYPERMETROPIA and would use convex LENS for correcting it.
the FOCAL LENGTH will be 1/2.5 METRE = 40 cm