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Ozone layerprotects us from Sun's harmful UV radiations. It shields the surface of the earth from ultraviolet (UV) radiation from the Sun. This radiation is highly damaging to organisms, for example, it is known tocauseskin cancer in human beings. There is increasedconcernabout the effect ofozone depletion.

The real impact of plastic bag litter is felt on wildlife both in the marine environmentand in rural areas.Tens of thousands of whales, birds, seals and turtles are killed every year from plastic bag litter in the marine environment as they often mistake plastic bags for food such as jellyfish.Plastic bags, once ingested, cannot be digested or passed by an animal so it stays in the gut. Plastic in an animal’s gut can prevent food digestion and can lead to a very slow and painful death.

from the relation.. of 1st order minima condition..

asin∅ = m(wavelength) , where m = 1 , sin∅ = sin30 = 1/2.

so, a = 1× 650 × 10^(-9) / 1/2 = 1350×10^-10 = 1.3× 10^(-7) m

answer is 1.3 × 10^(-7)m

and the closest value is option C.

What is Diffraction?

Diffraction is generally defined as the bending of light around corners such that it spreads out and illuminates areas where a shadow is expected. In general it is hard to separate diffraction from interference since both occur simultaneously.

In this experiment, we can observe the bending phenomenon of light or diffraction that causes light from a coherent source interfere with itself and produce a distinctive pattern on the screen called the diffraction pattern. Diffraction is evident when the sources are small enough that they are relatively the size of thewavelength of light. You can see this effect in the diagram below. For large slits the spreading out is small and generally unnoticeable.

For a we shall assume the slit width a << D. x`D is the separation between slit and source.

We shall identify the angular position of any point on screen by ϑ measured from the slit centre which divides the slit by a2 lengths. To describe the pattern, we shall first see the condition for dark fringes. Also let us divide the slit into zones of equal widths a2. Let us consider a pair of rays that emanate from distances a/s from each other as shown.

The path difference exhibited by the top two rays shown is

ΔL = a2sin θ

Remember that this is a calculation valid only if D is very large. For more details about the approximation check out our article in the Young’s Double Slit experiment.

We can consider any number of ray pairings that start from a distance a2 from one another such as the bottom two rays in the diagram. Any arbitrary pair of rays a distance a2 can be considered. We shall see the importance of this trick in a moment.

For a dark fringe, the path difference must cause destructive interference; the path difference must be out of phase by λ2. (λ is the wavelength)

For the first fringe,

ΔL = λ2 = a2sin θ

λ = a sin θ

For a ray emanating from any point in the slit there exists another ray at a distance a2 that can cause destructive interference.

Thus, at θ = sin−1λa, there is destructive interference as any ray emanating from a point has a counterpart that causes destructive interference. Hence, a dark fringe is obtained.

For the next fringe, we can divide the slit into 4 equal parts of a/4 and apply the same logic. Thus, for the second minima

λ2 = a4 sin θ

2λ = a sin θ

Similarly for the nth fringe, we can divide the slit into 2n parts and use this condition as

nλ = a sin θ

The central maximum

The maxima lies between the minima and the width of the central maximum is simply the distance between the 1st order minima from the centre of the screen on both sides of the centre.

The position of the minima given by y (measured from the centre of screen) is:

tanθ≈θ≈yD

For small ϑ, sin θ≈θ ,

λ = asin θ≈aθ

θ = yD = λa

y = λDa

The width of the central maximum is simply twice this value

Width of central maximum= 2λDa

Angular width of central maximum= 2θ = 2λa

The diffraction pattern and intensity graph is shown below.

Ans :- Longitudinal waves:-

A longitudinal waves is a wave where the movement of the medium is in the same direction as the wave.

This causes particles to move left and right inducing other particles to vibrate.

The primary wave in the earthquake is the longitudinal waves.

The longitudinal waves are one dimension.

☆Transverse waves:-

Transverse waves is a wave where the movement of the medium is at a right angle to the wave direction.

The particles move up and down as the wave mones horizontally.

The secondary waves in a earthquake is the transverse waves.

The transverse waves are the two dimension.

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Theconductor istypically raised above thebuildingto take the shock before thelightning can strikethebuilding.

As thelightning strikestheconductor, it passes through its bodyandinto the ground thus saving thebuildingstructure from any damage due to the flow of such high charge.

Answer will be option 2). because it's the third ring after the principal maxima

Diffraction refers to various phenomena that occur when a wave encounters an obstacle or a slit. It is defined as the bending of waves around the corners of an obstacle or aperture into the region of geometrical shadow of the obstacle.

The bending of light at the edge of an obstacle and hence its encroachment into the region of geometrical shadow is known as “diffractionof light”.Classification of diffraction phenomena: ... They are (1) Fresnel class ofdiffractionand (2) Fraunhofer class ofdiffraction.

We can define two distincttypes of diffraction: (a) Fresneldiffractionis produced when light from a point source meets an obstacle, the waves are spherical and the pattern observed is a fringed image of the object. (b) Fraunhoferdiffractionoccurs with plane wave-fronts with the object effectively at infinity.

a)Diffractionoccurs when a wave encounters an obstacle or a slit these characteristic behaviors are exhibited when a wave encounters an obstacle or a slit that is comparable in size to its wavelength, whereasInterferenceis the phenomenon where waves meet each other and combine additively or substractively to form

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Every particle in the universe attracts every other particle with a force along a line joining them. The force is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

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The malus law stating that the intensity of a beam of plane-polarized light after passing through a rotatable polarizer varies as the square of the cosine of the angle through which the polarizer is rotated from the position that gives maximum intensity.

Thejoule'sfirstlawshows the relationship betweenheatproduced by a flowing electric current through a conductor.

The amount of generated heatis proportional to wire's electrical resistance when the current in the circuit and the flow of current is not changed

Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points

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Ans :- Malus'law - Thelawstating that the intensity of a beam of plane-polarized light after passing through a rotatable polarizer varies as the square of the cosine of the angle through which the polarizer is rotated from the position that gives maximum intensity.

Laws of reflection of light is stated as the followingLaws of reflection:According to the laws of reflection,

i. The angle of incidence is equal to the angle of reflection.

ii. The incident ray, the normal at the point of incidence, and the reflected rayAlllie in the same plane.Here"all lie on the same plane" means thatthe incident ray, the normal at the point of incidence, and the reflected ray lie in the same plane

Snell's law (also known as Snell–Descartes law and the law of refraction) is a formula used to describe the relationship between the angles of incidence and refraction, when referring to light or other waves passing through a boundary between two different isotropic media, such as water, glass, or air.

Snell's law is ratio of sine of angle of incidence to sine of angle of refraction is a constant for a given pair of media and colour.constant=sine of (i)/sine of (r)Refractive index is defined as number which is used to measure the bending of light when it passes from one medium to another.Refractive is the ratio of speed of light in vacuum to the speed of light in medium.It can be mathematically represented as n=c/vSnell's law is only applicable if there is availability of two medium since the light bends only when it passes from one medium to another.

option (c) is correct.

thanku

option c is the correct answer

Electric motor: A motor is a device which converts electrical energy into mechanical energy.Principle of motor : A motor works on the principle that when a rectangular coil is placed in a magnetic field and current is passed through it. A force acts on the coil which rotates it continuously

When electric current is passed into the rectangular coil, this current produces a magnetic field around the coil.

The magnetic field of horse shoe-type magnet then interacts with the magnetic field of the coil and causes the coil to rotate continuously.

If ABCD is in horizontal position current from battery enters the coil through brush $B _{ 1 }$, and commutator half ring C:. The current flows in the direction ABCDand leaves via ring and brush $B _{ 2 }$

The direction of current is from A to B, the direction of current is from C to D. The force on side AB of the coil is in the downward direction. Whereas the force on the side CD of the coil is in the upward direction. ABCD rotate in anti-clockwise direction.

While rotating when the coil reaches vertical position then the brushes $B _{ 1 }$ and $B _{ 2 }$ will touch the gap between the commutator rings and current to the coil is cut off. But the coil does not stop rotating because it has already gained momentum.

The coil CD comes on the left side and AB comes to the right side. Again they come in contact with brush $B _{ 1 }$ Current direction is reversed.

The reversing of current in the coil is repeated after every half rotation due to which the coil continue to rotate as long as current from the batter is passed through it. The rotating shaft of electric motor can drive a large number of machines which are connected to it.

RAD or Rapid Application Development process is an adoption of the waterfall model; it targets at developing software in a short span of time. RAD follow the iterative

Advantages:1.Flexible and adaptable to changes

2.It is useful when you have to reduce the overall project risk

3.It is adaptable and flexible to changes

4.It is easier to transfer deliverables as scripts, high-level abstractions and intermediate codes are used

5.With less people, productivity can be increased in short time

The SI unit of luminous intensity is candela.

The intensity of radiation of given wavelength represent the number of energy quanta or photons incident per unit area per time, with each photon having the same energy. As each photon ejects only one electron, the number of ejected photo electrons increases with increase in the intensity of incident radiation.

It would be more bright then present moonit's temp would be increasedthere would be no night.

The answer could be Option b.

I think c

Option Cas S= A+ B( x OR)= 0

nowA.B= C= 1

GIVEN::

K.E = P.E =>1/2MV​²=MGH

=>H=1/2V²/g

PUTTING VALUES

H=1/2*20*20/9.8

= 20.4m

thanku sir

In order for us to see an object that is non-luminous, it must reflect some of the light it receives from a luminous source, such as the Sun. Most of the objects we see, such as cars, clouds or even the Moon, are not luminous; it is just that they reflect sunlight.

convex lens is the correct answer of the given question

The combination will behave as a convex lens. The numeric answer of +2-1 is +1 and positive focal length denotes convex lens.

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11)

Asolenoidis a long coil of circular loops of insulated copper wire.Magneticfield lines are produced around thesolenoidwhen a current is allowed to flow through it. Hence, one end of thesolenoid behavesas a north pole and the other endbehaves as a south pole.

Attraction may occur between two oppositely charged bodies or a charged body and an uncharged one. That is why in attraction, one is not sure if both bodies are charged, However in repulsion, there are two bodies that have the same charge. That is why repulsion is the sure test of electrification.

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