1.explain the mechanism of light propagation 6. Electric Flux 14.7 Heating effect of current:-- Q1.

14.7 Heating effect of current:-- Q1. State Biot-Savart’s law for the magnetic field
through optical fiber. -In electromagnetism, electric flux is the measure When an electric current flows through a conductor, due to a small current element:-
_ In optical fibers, propagation of light takes place of the electric field through a given surface, it experiences some resistance due to the presence of If dl represents the small section of a long current-
due to total internal reflection. When light falls although an electric field in itself cannot flow. The free electrons carrying conductor having a current of I and r is
one end of the optical fiber; it gets refracted into electric field E can exert a force on an electric colliding with the atoms of the conductor. This the distance
the fiber. The refracted ray of light falls on the charge at any point in space. The electric field is resistance results in the generation of heat, which is between the conductor and point let’s say P and θ
interface separating the fiber and coating an angle the gradient of the potential. known as the heating be the angle between dl and r. According to Biot-
which is greater than the critical angle. effect of current. Savart
Formula:- ϕ E=E.S=EScos θ
# Thus the TIR can take place. The light travels 15. Electric power:-- law, the magnitude of dB at point P ,
the entire length of the fiber and arrives at other 7.Electric potential and potential difference. Electric power is the rate at which electrical energy is i. is directly proportional to the current I and the
ends of the fiber without any loss in its intensity -Electric potential is the work done per unit charge transferred or consumed in an electrical element length dl.
even if the fiber is rounded and curved. to bring the charge from infinity to a point in an circuit. It is measured in watts (W) and is given by the ii. is inversely proportional to the square of
Light Propagation in Optical Fibers is a electric field. Potential difference is the difference formula: distance r.
phenomenon that involves the transmission of between the potentials between two points in the P=I×V iii. is proportional to the sine of angle between the
light through a fiber optic cable. This technology electric field. Electric potential is defined at a where P is the power in watts, I is the current flowing wire segment dl and the line joining the point P to
has revolutionized the field of point. in amperes (A), and V is the voltage across the circuit the wire
telecommunications, enabling the fast and Electric Potential is a key term in the field of in volts (V). segment.
efficient transmission of data over long distances. electricity, as it requires a potential difference to therefore,
initiate the movement of electrons and therefore Electric energy:-- dB ∝
2. state the criteria for the phenomenon of total produce electricity. Further, in the upcoming Electric energy is the amount of electrical work done Idl sin θ
internal reflection of light to take place. sections, we will discuss electric potential, in a circuit, and it is measured in joules (J). r
- For total internal reflection to occur, two potential difference, and the difference between The energy consumed by an electrical device is equal 2
conditions must be met: The index of refraction electric potential and potential difference. to the power consumed multiplied by the time for or, dB =
must decrease across the boundary in the which it is in use. µ0
direction of light refraction. The angle of incidence 8. Capasitor and its working: The formula for electric energy is: 4π
of the light ray must exceed the critical angle of Unlike the battery, a capacitor is a circuit E=P×t Idl sin θ
the interface. Ray must travel from denser to component that temporarily stores electrical where E is the electric energy in joules (J), P is the r
rarermedium. energy through distributing charged particles on power consumed in watts (W), and t is the time for 2
For total internal reflection to occur, two (generally two) plates to create a potential which the device where µ0
conditions must be met: The index of refraction difference. A capacitor can take a shorter time is in use in seconds (s). 4π
must decrease across the boundary in the than a battery to charge up and it can release all is proportional constant and µ0 is the permeability
direction of light refraction. The angle of incidence the energy very quickly. 16. Thermoelectric effect -1. Seebeck effect:-- of the vacuum or air medium.
of the light ray must exceed the critical angle of Types of capasitor:-a.Ceramic Capacitors. The Seebeck effect is the basis of the thermoelectric
the interface. Ray must travel from denser to b.Film Capacitors. effect. It is the phenomenon where a temperature 2. Write down the expression for the magnetic
rarermedium. c.Power Film Capacitors. gradient across field developed inside a long solenoid carrying a
3. Brewster's law. d.Electrolytic Capacitors. two different materials or conductors causes an current:-
When an unpolarized light of known wavelength is e.Ceramic capacitors. electric potential difference between them. The The magnetic field developed inside a long
incident on a transparent substance surface, it f Film capacitors. magnitude of the voltage solenoid carrying a current I is µ0nI, where µ0 is
experiences maximum plan polarization at the g.Paper Capacitors. produced by the Seebeck effect depends on the the permeability
angle of incidence whose tangent is the refractive h Electrolytic capacitors. temperature difference and the properties of the of the vacuum and n is no. of turns per unit length.
index of the substance for the wavelength. materials used.
4. State Gauss law in electrostatics. Using the law 9.Dielectric break down . 2.Peltier effect:-- 3. Write rule gives the direction of the force on a
, derive an expression for the electric field due to Dielectric breakdown is the failure of an insulating The Peltier effect is the inverse of the Seebeck effect. current carrying conductor when placed in
a uniformly charged sphere. material to prevent the flow of current under an It is the phenomenon where a temperature magnetic
- Gauss law states that the total electric flux out of applied electrical stress. The breakdown voltage is difference across a filed? State it.
a closed surface is equal to the charge enclosed the voltage at which the failure occurs, and the junction of two different materials causes a heat flow Ans. The rule that gives the direction of the force
divided by the permittivity. The electric flux in an material is no longer electrically insulating. across the junction. This effect is commonly used in on a current-carrying conductor when placed in a
area is defined as the electric field multiplied by thermoelectric magnetic field
the area of the surface projected in a plane and 10. Ohm’s law:-- cooling devices, where the Peltier effect is used to is known as the ”Fleming’s left hand”. It can be
perpendicular to the field. According to Ohm’s law, the electric current transfer heat from one side of the device to the other stated as follows:
- Electric field due to a uniformly charged thin through a conductor is directly proportional to the Fleming’s left hand rule states that if we stretch
shell: potential difference 17.Electro motive force (EMF)::-- the fore finger, the central finger and the thumb of
In the diagram, O is the centre of the spherical across it, provided the physical conditions such as EMF is the short form of electromotive force. EMF of our
shell of radius R, and charge enclosed by the temperature and pressure remain unchanged. a cell or battery equals the potential difference left hand at right angles to each other and hold
spherical shell is q. Let V be the potential difference applied across a between its them in such a way that the fore finger points in
Let a point A is outside the spherical shell, where conductor and I be the current flowing through it. terminals when these are not connected (open the direction
we have to calculate the electric field.The distance According to circuit) externally of magnetic field and the central finger points in
between the centre of spherical shell and the Ohm’s law, E = V + Ir the direction of motion of positively charged
point A. V ∝ I (6) where r is the internal resistance of the battery, I be particle, then the
ϕ=E.Scosθ or, V = RI flowing in the circuit and V is the potential difference thumb will point in the direction of the Lorentz
So, ϕ=E.4πr or, between two terminals of the battery. force.
2 V 18.what is specific resistance of a material obtain si Q4. State the laws of electromagnetic induction .
−−−−−−−−−−−−−−(1) I unit.:- Ans. The laws of electromagnetic induction are
As per gauss law, =R Specific electrical resistance is also known as electric Faraday’s Laws and Lenz’s law.
ϕ= where constant of proportionality R signifies the resistivity is a property of material defining how Faraday’s Law
ϵ electrical resistance offered by a conductor to the strongly can the material oppose the flow of electric Faraday’s law states that an emf is induced across
00 flow of electric current. current. SI unit of electrical resistivity is ohm-meter a loop of wire when the magnetic flux linked with
qq−−−−−−−−−(2) and is represented as ⍴. the surface
From equation (1) and (2) 11. Krichhoffs first law :- bound by the loop changes with time. The
E.4πr Kirchhoff ’s First Rule (Junction Rule) : 19. Wheatstone Bridge. magnitude of induced emf is proportional to the
2 It states that the sum of all currents directed A Wheatstone bridge is an electrical circuit used to rate of change of
= towards a junction (point) in an electrical network measure an unknown electrical resistance by magnetic flux.
ϵ is equal to the sum balancing two legs of a bridge circuit, one leg of |E| =
oo of all the currents directed away from the which includes the unknown component. The ∆φ
q junction. In other words, the algebraic sum of all primary benefit of the circuit is its ability to provide ∆t
Now, currents at a junction is zero mathematicaly . extremely accurate measurements. where E is the induced EMF, ∆φ is the change in
E= 12. Krichhoffs second law :-• magnetic flux through the loop, and ∆t is the time
4πϵ The algebraic sum of the products of the currents 20. Define watt- hour . taken for
oo and resistances in any closed loop of an electrical Definition- Watt-hour is an alternate unit of energy the change to occur.
r network is used to measure the electrical energy equivalent to a Lenz’s Law
2 equal to the algebraic sum of electromotive forces power consumption of one watt for one hour. As we Lenz’s law is a consequence of Faraday’s laws,
q acting in the loop. In other words, The algebraic know that the power is equal to the energy which states that the direction of the induced EMF
This is the electric field at the distance r, outside sum of all the consumed in per unit time, so the energy will be the is such that it
from the shell. potential differences along a closed loop in a product of the power and the time. opposes the change that produced it. In other
5.coulomb's law. circuit is zero. Mathematically, words, the induced current creates a magnetic
- Coulomb's inverse-square law, or simply 21. What is superconductivity. field that opposes
Coulomb's law, is an experimental law of physics 13.Joule’s Law:-- Superconductivity is the property of certain materials the original magnetic field.
that calculates the amount of force between two The amount of heat produced in a conductor is to conduct direct current (DC) electricity without E=−
electrically charged particles at rest. This electric directly proportional to the square of the current energy loss when they are cooled below a critical ∆φ
force is conventionally called electrostatic force or flowing through it, temperature . ∆t.
Coulomb force. and the resistance of the conductor, and the time
for which the current flows through it. This
relationship is expressed by
the following formula, known as Joule’s Law:
H = I 2RT
Q5. Define coefficient of mutual inductance of a 1.What is a hologram in simple terms? 1.What is Carey frister brudge
pair . ans-A hologram is a photographic recording of a light Ans-The bridge circuit that can calculate
Ans. The coefficient of mutual induction is defined field, rather than an image formed by a lens. The medium resistances or can compare and
as the ratio of emf induced in the secondary coil to holographic medium, for example the object measure the two large/equal resistance values
the rate produced by a holographic process (which may be with small variations is known as Carey foster
of change of current in the primary coil. It is a referred to as a hologram) is usually unintelligible bridge. It is the modified form of Wheatstone’s
measure of induction between two circuits. when viewed under diffuse ambient light. bridge circuit. It is also referred to as the
Mathematical method of small resistances.
representation 2.What are 5 properties of X-rays?
M= The X-Rays properties are given below: 2. Di electric breakdown :-
dI dt They have a shorter wavelength of the Ans-Dielectric breakdown is the failure of an
where is induced emf and dI electromagnetic spectrum. insulating material to prevent the flow of
dt is the rate of change of current in the given coil. Requires high voltage to produce X-Rays. current under an applied electrical stress. The
Q6. State Fleming’s right hand rule. They are used to capture the human skeleton breakdown voltage is the voltage at which the
Ans. Fleming’s Right Hand Rule states that if we defects. failure occurs, and the material is no longer
arrange our thumb, forefinger and middle finger of They travel in a straight line and do not carry an electrically insulating.
the right-hand electric charge with them.
perpendicular to each other, then the thumb They are capable of travelling in a vacuum. 3.Effect of Dielectric on Capacitance
points towards the direction of the motion of the Ans-We usually place dielectrics between the
conductor relative 1. What is an intrinsic semi conductor two plates of parallel plate capacitors. They can
to the magnetic field, the forefinger points Ans -An intrinsic (pure) semiconductor, also called fully or partially occupy the region between the
towards the direction of the magnetic field and an undoped semiconductor or i-type semiconductor, plates. When we place the dielectric between
the middle finger is a pure semiconductor without any significant the two plates of a parallel plate capacitor, the
points towards the direction of the induced dopant species present. The number of charge electric field polarises it.
current. carriers is therefore determined by the properties of The surface charge densities are σp and – σp.
Q7.Biot-Savart law . the material itself instead of the amount of When we place the dielectric fully between the
Ans .If dl represents the small section of a long impurities. two plates of a capacitor, then it’s dielectric
current-carrying conductor having a current of I constant increases from its vacuum value.
and r is the distance between 1. What is population inversion?
the conductor and point let’s say P and θ be the Ans-population inversion, in physics, the
angle between dl and r. According to Biot-Savart redistribution of atomic energy levels that takes
law, the magnitude of place in a system so that laser or maser action can
dB at point P occur. Normally, a system of atoms is in temperature
i. is directly proportional to the current I and the equilibrium and there are always more atoms in low
element length dl. energy states than in higher ones.

Peltier Effect: Heat is absorbed or released at the 1.what is simple harmonic motion?
junction of two materials when an electric current Ans-In mechanics and physics, simple harmonic
flows through them. It is used in thermoelectric motion is a special type of periodic motion an object
coolers and heaters. experiences due to a restoring force whose
magnitude is directly proportional to the distance of
Joule Effect: Heat is generated in a conductor the object from an equilibrium position and acts
when an electric current passes through it due to towards the equilibrium position.
resistance. It is responsible for the heating of
electrical appliances and is important in circuit 1.frequency and eavelength and their relationship
design. Ans-The frequency and wavelength are indirectly
proportional to each other. More is the wavelength,
1. What is an intrinsic semi conductor lesser is the frequency and vice-versa. The speed at
Ans -An intrinsic (pure) semiconductor, also called which a wave travels is equal to the product of its
an undoped semiconductor or i-type frequency and wavelength, which justifies the link
semiconductor, is a pure semiconductor without between these two parameters.
any significant dopant species present. The
number of charge carriers is therefore determined what do you mean by free and damped oscillations
by the properties of the material itself instead of Ans-(a) Free oscillations: simple harmonic motion
the amount of impurities. with a fixed amplitude and period and no external
disturbances. (b) damped oscillations – simple
2. What are extrinsic semi conductor . harmonic motion with diminishing amplitude and
Ans -Extrinsic semiconductors are semiconductors fluctuating period as a result of external or internal
that are doped with specific impurities. The damping forces.
impurity modifies the electrical properties of the
semiconductor and makes it more suitable for 1.law of optics
electronic devices such as diodes and transistors. Ans-Laws of reflection: The principle when the light
rays fall on a smooth surface, the angle of reflection
3.What kind of impurity is chosen to make n-type is equal to the angle of incidence.
and p-type semiconductor.gives examples. Laws of refraction: The incident ray, refracted ray,
Ans - Impurities such as Arsenic, Antimony, and the normal to the interface of two media at the
Phosphorous and Bismuth (elements having five point of incidence all lie on the same plane.
valence electrons) are added in N-type
semiconductors. Impurities such as Aluminium, 1.Define specific resistance and state its SI unit.
Gallium and Indium (elements having three
valence electrons) are added in P-type Ans-Specific resistance or resistivity (p), of a
semiconductors. conductor, is defined as the resistance of a conductor
of unit length and unit area of cross-section. the
4.What is an insulator short answer? factors affecting the resistance of a
Ans -Materials that do not allow electricity to pass conductor, the resistance is given by,
through them are called insulators. Insulators R=P=
oppose electric current and so they are used as a Its unit is ohmm
protection from the dangerous effects of Specific resistance or resistivity is the characteristic
electricity. Examples of insulators are glass, air, property of the material of the conductor and
wood, plastic and rubber. depends only on the nature of the material and
2.What is conductor in science? temperature.
A conductor, or electrical conductor, is a substance
or material that allows electricity to flow through 1.What is Wheatstone Bridge?
it. In a conductor, electrical charge carriers, usually Ans-Wheatstone bridge, also known as the
electrons or ions, move easily from atom to atom resistance bridge, calculates the unknown resistance
when voltage is applied. by balancing two legs of the bridge circuit. One leg
includes the component of unknown resistance.
What are the 3 unique properties of laser? The Wheatstone Bridge Circuit comprises two known
Understanding laser physics involves resistors, one unknown resistor and one variable
comprehending the principles of stimulated resistor connected in the form of a bridge. This
emission and population inversion. Laser light is bridge is very reliable as it gives accurate
unique among ordinary sources due to properties measurements.
like coherence, monochromaticity, and
directionality.