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the answer could be option 2

option 1)10 N is the correct answer

25)a)12 kgbecause Mass of a body remains same anywhere in space. Thus, the body of mass M on earth will have mass M on moon also.26)c)weight on moon =weight on earth/6 =120/6 =20kg

Work = F x s = m x a x s

a = (v -u)/t = 5 ms-2

s = (v2-u2)/2a = (2500 - 1600)/10 = 90 m

Work = m x a x s = 20 x 5 x 90 = 9000 kgm2s-

An object float or sink depends on its own density and the density of the liquid which it is placed in. If buoyant force is less than the weight of the object, then the object will sink in water. This upward force acting on the object, when an object is immersed in water is called the buoyant force.

No, it depends on the density of the object. If it's density is less than that of oil, it will sink.

The density of an object determines whether it will float or sink in another substance. An object will float if it is less dense than the liquid it is immersed in.Liquids, like oil, create less buoyancy than water, so objects that float in water will sink in oil.

Source: A body at a higher temperature 1 1 T.Heat Q is extracted from this body by the working substance and hence it is called a ‘source’ Sink: A body at a lower temperature 2 2 T .Heat Q is rejected by the working substance to this body and hence is called a ‘sink’.

The phase velocity is: vp = w/k. The function w(k), which gives w as a function of k, is known as the dispersion relation. If w is directly proportional to k, then the group velocity is exactly equal to the phase velocity. A wave of any shape will travel undistorted at this velocity

This law states that the flux passes through any closed surface is equal to the ratio of total charge inside the surface to the permittivity of the medium

In physics, Gauss's law, also known as Gauss's flux theorem, is a law relating the distribution of electric charge to the resulting electric field. The surface under consideration may be a closed one enclosing a volume such as a spherical surface.

Gauss theorem states that the total electric flux through any closed surface surrounding a charge, is equal to the net positive charge enclosed by that surface.

Gauss's law states that the net flux of an electric field in a closed surface is directly proportional to the enclosed electric charge.

This law states that the flux passes through any closed surface is equal the ratio of total charge inside the surface to the permitivity of the medium.

Water is a liquid and it is the property of a liquid that it can't fill its container completely .So some space on top of the water left unfilled by water during filling the tanker

Some space is left at the top of the tanker as when the tanker comes to motion ,the water tries to remain at rest and splashes backward due to inertia of rest.Therefore, to avoid overflowing of water, some space is left at the top of the tanker

what is a liquid and it is the property of a liquid that it can't feel its container completely so some space on top of the water left unfilled by water during filling the tanker

No, those packets do not take same time to reach the surface of the earth. Because the value of g (i.e., acceleration due to gravity is) different at poles and equator due to rotation of the earth and is given by g’= g -a>2rsin0 and at poles 0 = 0 whereas at equator 0 = 90°.

Since, g is greatest at the poles than at the equator. So, packet dropped above the north pole will reach first at the surface of the earth.

magnification, m = -1 = v/u

[ here magnification is negative. it means lens must be convex lens. ]

or, v = -u .........(1)

a/c to question,

v + (-u) = 60cm ..........(2)

from equations (1) and (2),

-u -u = 60cm

or, -2u = 60cm

or, u = -30cm

v = 30cm

use lens maker formula, 1/v - 1/u = 1/f

or, 1/30 - 1/-30 = 1/f

or, 1/60 = 1/f => f = 60cm

again, if the object is moved 20cm towards the lens .

u = -(30 - 20) = -10cm

f = +60cm

use lens maker formula, 1/v - 1/u = 1/f

or, 1/v - 1/(-10) = 1/60

or, 1/v = 1/-10 + 1/60 = (-6 + 1)/60

or, v = -12cm

hence, image is formed left side of lens

The magnification is -1 means the image is real and inverted and is of the same size as that of the object.so if the image is at a distance of 40cm from the mirror then the object is also at a distance of 40cm from the mirror (because the object is placed at C ie center of curvature of the mirror.if the object is moved 20cm towards the mirror the object is placed at F ie at the principal focus and the image is formed at infinity.the nature of the mage so formed is real inverted and highly enlarged.

The image of the flower stand will be 5 cm wide, as plane mirror produces no magnification.The image will be 2m inside the mirror surface.The image will move with the same speed of 1m/s towards the mirror.

Since, it's a plane mirror, it will not produce any kind of magnification. width will be 5m and image will be 2m away. the image will approach him at 1m/s.

Draw a labelled diagram of Hertz's experimental setup to 19971 produce electromagnetic waves. Explain the generation of electromagnetic waves using this setup

Thewaveson thesurfaceof thewaterare neither longitudinal nor transverse. We can see in animation that red ball, which simulates the molecule of thewater surface, moves in a circle path. So, thewaveon thewater surfaceis the superposition of transverse and longitudinal motions of the molecules.

what is your name

Properties of Electromagnetic Waves

Electromagnetic waves are composed of oscillating electric and magnetic fields at right angles to each other and both are perpendicular to the direction of propagation of the wave. Electromagnetic waves differ in wavelength (or frequency).

In an electro-negative wave the electric fieldE(vector) and the Magnetic fieldB(vector) oscillate perpendicular to each other and both are perpendicular to direction of propagation of wave.

The source that produce them and methods of their detection are different, but they have the following common properties :

Electromagnetic waves are propagated by oscillating electric and magneticfieldsoscillating at right angles to each other.

Electromagnetic waves travel with a constant velocity of3 x 108ms-1in vacuum.

Electromagnetic waves arenot deflectedby electric or magnetic field.

Electromagnetic waves can showinterferenceordiffraction.

Electromagnetic waves aretransverse waves.

Electromagnetic waves may bepolarized.

Electromagnetic waves needno mediumof propagation. The energy from thesunis received by the earth through electromagnetic waves.

Thewavelength(λ) and thefrequency(v) of electromagnetic wave is related as

c =vλ = ω/k

The S.I. unit of frequency isHertz.

1 Hertz = 1 c / s

The S.I. unit of wavelength is metre.

We however, often express wavelength inAngstromunit [ Å ]

1 Å = 10-10m

Also, 1 nanometer =l nm = 10-9m

The creation of all electromagnetic waves begins with a charged particle. This charged particle creates an electric field (which can exert a force on other nearby charged particles). When it accelerates as part of an oscillatory motion, the charged particle creates ripples, or oscillations, in its electric field, and also produces a magnetic field (as predicted by Maxwell’s equations).

Once in motion, the electric and magnetic fields created by a charged particle are self-perpetuating—time-dependent changes in one field (electric or magnetic) produce the other. This means that an electric field that oscillates as a function of time will produce a magnetic field, and a magnetic field that changes as a function of time will produce an electric field. Both electric and magnetic fields in an electromagnetic wave will fluctuate in time, one causing the other to change

Ans :- We perceive only the reflectedcolors. Thus, red is not "in" an apple. The surface of the apple is reflecting the wavelengths we see as red and absorbing all the rest. An object appears white when it reflects all wavelengths and black when it absorbs them all.

Thearea underavelocity-time graphis a representation of the displacement. If theareais over atimeinterval, then the displacement during thattimeinterval can be measured by thearea underthegraphbounded by thetimeinterval.

Latent heat is energy released or absorbed, by a body or a thermodynamic system, during a constant-temperature process. Two common forms of latent heat are latent heat of fusion and latent heat of vaporization.

Anelectromagnetic wave, although itcarriesno mass,does carry energy. It also hasmomentum, and can exert pressure (known asradiationpressure). ... Theenergycarried by anelectromagnetic waveis proportional to the frequency of thewave.

It is the heat required to raise the temperature of the unit mass of a given substance by a given amount (usually one degree).

A wind turbine captures the wind to produce energy. The wind makes the rotor spin; as the rotor spins, the movement of the blades drives a generator that creates energy. The motion of the wind turbine turning is calledkineticenergy, this power is converted into electricity

D÷T=100÷50=50snail covers 50km/h

D÷T=100/50=50 km/h small cover

100/50=50 average of cover

Yes, electronic devices can charge their batteries through various methods without being plugged into a source of electricity. What all the different methods have in common is that they absorb energy that is in some other form (heat, light, vibrations, radio waves, etc.) from the external environment and then convert the energy into electrochemical energy that is stored in the device's batteries. While such methods are scientifically sound and have already been successfully demonstrated, the energy captured from the outside environment is often not enough to be practically useful. Intense research is currently underway to make energy capture more efficient, and breakthroughs are beginning to be achieved in this area. Many phones are already available that offer wireless charging. Let us look at the main types of energy a device can use to charge itself without being plugged in.

Solar panels are able to capture energy from sunlight and recharge batteries. Miniaturized solar panels are available to recharge portable electronic devices without needing to plug them into the wall. Public Domain Image, source: NASA.Solar EnergyThe oldest energy capture method used on electronic devices is most likely solar energy capture using a solar cell. Small calculators that use solar cells to help power them have been around for decades. Solar cells (photovoltaics) absorb ordinary light and convert it directly to electricity using layers of semiconductors. While photovoltaics are well understood and commercially established at this point, there are several drawbacks in using photovoltaics to recharge a handheld electronic device. The main drawback is that the light-to-electricity conversion process of photovoltaics is inefficient. Recent advances have however been made that boost the efficiency, and intense research is ongoing to continue to increase the efficiency. The other drawback is that for typical lighting levels, light does not contain that much energy to begin with. For traditional solar cells to provide reasonable output power, they have to be large in size, out in the direct sunlight for a long time, and oriented towards the sun. of these conditions is very practical for a cell phone that you keep in your pocket or your hand most of the day.

a) In household supply, Alternating current(AC) is used.

b) Direct Current(DC) is given by the cell.

1. current used in household supply is Alternating current(AC)2. current given by cell is direct current (DC)

Heat is a form of energy, and the quantity is measured in the same units as any other form of energy. The SI unit of energy, the joule, is applied to heat as well as any other energy. As for the quantities of heat transferred, it does not matter by what physical process the heat is lost. The critical parameters are the initial and final temperatures, giving a temperature difference, and the specific heat and volume of the material from which the heat is lost.

As a working example: the calorie is defined as the amount of energy required to raise the temperature of 1g of water by 1ºC, so raising the temperature of 100ml (100g) of water from 20ºC to 25ºC requires 100 x 5 = 500cal. Otherwise expressed: the specific heat of water is 1cal/g. Aluminium has a specific heat of 0.215cal/g, meaning that to heat aluminium one needs much less heat. To heat an aluminium block weighing 100g through 5ºC requires only 100 x 5 x 0.215 = 108cal. 1cal = approx 4.2joules.

Thespecific heatis the amount ofheatper unit mass required to raise the temperature by one degree Celsius. The relationship betweenheatand temperature change is usually expressed in the form shown below where c is thespecific heat. ... As a result, water plays a very important role in temperature regulation

Bro the answer is option 3

germanium is a semiconductor

Germanium is a semiconductor

An n-type semiconductor is made by adding a small amount of a Group-V element such as phosphorous (P) or arsenic (As) to the intrinsic semiconductor. Group-V elements have five valence electrons per atom.

A p-type semiconductor is made by doping an intrinsic semiconductor with Group-III elements such as boron (B) or aluminium (Al). In these elements, there are only three valence electrons per atom.

Intrinsic semiconductors are elements with four valence electrons per atom, i.e. elements that occur in “Group-IV” of the periodic table such as silicon (Si) and germanium (Ge).

A doped semiconductor is referred to as an extrinsic semiconductor.

2)The terms n- and p-type doped do only refer to the majority charge carriers. Each positive or negative charge carrier belongs to a fixed negative or positive charged dopant.

p and n type materials are NOT positively and negatively charged.

An n-type material by itself has mainly negative charge carriers (electrons) which are able to move freely, but it is still neutral because the fixed donor atoms, having donated electrons, are positive.

Similarly p-type material by itself has mainly positive charge carrier (holes) which are able to move relatively freely, but it is still neutral because the fixed acceptor atoms, having accepted electrons, are negative.

As stearic acid is saturated it decolourised iodinehence option a

Thermoplastic polymers are linear (slightly branched) long chain polymers, which can be repeatedly softened and hardened on heating. Hence, they can be modified again and again. Examples include polythene, polystyrene.

Thermosetting polymers are cross-linked or heavily branched polymers which get hardened during the molding process. These plastics cannot be softened again on heating. Examples of thermosetting plastics include bakelite, urea-formaldehyde resins.

Toform P-type Semiconductorthere is addition of some trivalent impurity such as gallium, aluminium etc in intrinsicsemiconductor.As trivalent impurity has three electrons in its valence shell and when it creates bond with silicon atom there will be deficiency of electron in valence shell which is called hole.

AnN-Type semiconductoris created by adding pentavalent impurities like phosphorus (P), arsenic (As), antimony (Sb), or bismuth (Bi). A pentavalent impurity is called a donor atom because it is ready to give a free electron to asemiconductor. The impurities are called dopants.

it behaves like an insulator

it behaves like insulator

(A) a conductor this answear

Answer:c)an insulatorExplanation:At 0k,electrons do not have sufficient energy to jump fromvalance band to conduction band and therefore it acts as aninsulator.

it behaves likes an insulator

it behave like a insulator

When small amount of antimony (pentavalent) is added to germanium crystal then crystal becomes n-type semi condcutor. Therefore, there will be more free electron than holes in the semiconductor.

An intrinsic semiconductor is an undoped semiconductor. This means that holes in the valence band are vacancies created by electrons that have been thermally excited to the conduction band, as opposed to doped semiconductors where holes or electrons are supplied by a “foreign” atom acting as an impurity.

Anextrinsic semiconductoris asemiconductordoped by a specific impurity which is able to deeply modify its electrical properties, making it suitable for electronic applications (diodes, transistors, etc.) or optoelectronic applications (light emitters and detectors).