Integration of cos⁴x.
Answer:-
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Mean value of alternating current.
Answer:- Mean value of a.c. is that value of steady current which sends the same amount of charge, through a circuit, in same time as is done by a.c. in half its cycle.
Tautomerism.
Answer:- In this type of Isomerism, the isomers exist in dynamic equilibrium with eachother.When a ketone and enol isomers exist in equilibrium, this type is called keto-enol tautomerism.For keto-enol tautomerism, there should be an alpha hydrogen atom in the carbonyl compound.
Impure spectrum.
Answer:- Impure spectrum is a spectrum in which the constituent colours overlap each other.
What is SP3 hybridisation ?
Answer:- When all the four orbitals of L-shell (2S,2Px,2Py,2Pz) get mixed up, four SP3 hybrid orbitals result.They are exactly similar in shape and are directed to the four corners of regular tetrahedron.The bond angle in it is 109⁰28'.Each SP3 orbital has 25% S-character and 75% P-character.
Current density.
Answer:- Current density J, at any point inside a conductor, is a vector quantity whose magnitude is equal to the current per unit area through an infinitesimal area at that point, the area being held perpendicular to the direction of flow of charge and its direction is along the direction of the flow of positive charge.
What is SP hybridisation ?
Answer:- When two orbitals of L-shell (2S,2Px or 2Py or 2Pz) get mixed up, two hybrid orbitals result.These two SP orbitals are exactly similar in shape and make an angle of 180⁰.Each SP orbital has 50% S-character and 50% P-character.
Definition of one ampere.
Answer:- One ampere is the current which when maintained in two parallel straight conductors, of infinite extent and negligible area of cross-section separated one metre apart, in vacuum would produce a force of 2×10^-⁷ per metre length of the conductors.
What is SP2 hybridisation ?
Answer:- When three orbitals of L-shell(2S,2Px,2Py) get mixed up, three hybrid orbitals result.These are exactly similar in shape and are directed to the three corners of a regular tetrahedron. The bond angle in it is 120⁰.Each SP2-orbital has 33% S-character and 67% P-character.
Catenation.
Answer:- The self linking ability of an atom with other atoms of the same element is known as catenation.Carbon possesses maximum tendency for catenation in the periodic table.
What is electromagnet ?
Answer:- A magnet excited by the electric current flowing through the wires wound over soft iron pieces is called an electromagnet.
Potential difference.
Answer:- Potential difference, between any two points, in an electric field is defined as the work done in taking a unit positive charge from one point to the other against the electric field.
Horse shoe magnet 🧲.
Answer:- A magnet bent into U-shape and having its free poles facing each other.
Nuclear reaction.
Answer:- It is a reaction in which only the nuclei take part.Orbital electrons have no contribution in it.The reaction is known as a nuclear reaction.
Nuclear fission.
Answer:- Nuclear fission is the process by which a nucleus breaks up in such a way that the two products obtained are of comparable sizes.
What is Source charge ?
Answer:- It is the charge distribution or a charged body whose electrostatic effect at a point away from it is to be analysed.For application of Coulomb's law the source charge has to be a point charge.
One coulomb of charge.
Answer:- One coulomb of charge is defined as that charge which when placed, in air, at a distance of 1 metre from an equal and similar charge repels it with a force of 9×10⁹ newton.
Why charge is a scalar quantity ?
Answer:- Charge does not possess any direction.So, it is a scalar quantity.No doubt charge is capable of travelling in a particular direction depending upon the potential gradient, but no characteristic direction can be assigned to charge itself.
Electric field intensity.
Answer:- The strength of an electric field is measured by noting force experienced by a unit positive charge placed at that point.The direction of field is given by direction of motion of a unit positive charge if it were free to do so.
potential energy of an electric dipole.
Answer:- Potential energy of an electric dipole, in an electrostatic field, is defined as the work done in rotating the di-pole from zero energy position to the desired position in the field.
Dipole moment.
Answer:- Dipole moment measures the degree of polarity of a molecule.In case of diatomic molecules, more the difference in electronegatives of two bonded atoms, more is the polarity and hence more is the value of dipole moment.
Coulomb's law in electrostatics.
Answer:- It states that,“the electrostatic force of attraction or repulsion between two charged bodies is directly proportional to the product of their charges and varies inversely as the square of the distance between the two bodies.
Permittivity.
Answer:- It is a characteristic of a medium which determines the capability of the medium to convey the effect of a charge from one point to another in the same medium.
Additive nature of charge.
Answer:- Total charge on an extended body is equal to the algebraic sum of charges located at different points or in different regions of the body.
Invariance of charge.
Answer:- The amount of charge remains the same when converted from one inertial frame of reference to another inertial frame.
What is atom ?
Answer:- Atom is the smallest particle of matter which can take part in a chemical reaction.
What is charge ?
Answer:- A charge is a fundamental characteristic property of elementary particles of matter which can explain certain forces of interaction and some types of interaction energies.
Chemical equations.
Answer:- A chemical equation is defined as the short-hand representation of a true chemical reaction with the help of symbols and formulae.
Critical angle.
Answer:- Critical angle is the angle of incidence of a ray of light in denser medium such that it's angle of refraction in the rarer medium is 90⁰.
Magnetic induction.
Answer:- Magnetic induction at any point inside a matter is defined as numbers of lines of force associated per unit area when area is held perpendicular to the lines of force.
Hydrogen bond.
Answer:- Hydrogen bond is defined as the force of attraction which binds hydrogen atom of one molecule with the highly electronegative atom(Fluorine, Oxygen and Nitrogen)of another molecule of the same or of different substance.
d-block elements.
Answer:- Those elements in which last electron enters into the d-sublevel of the penultimate main energy level are called d-block elements.
Susceptibility.
Answer:- It is defined as the ratio between intensity of magnetisation to the magnetising field strength.Denoted by ‘ χ’. I.e χ=I/H
Chemical compound.
Answer:- A chemical compound is defined as a substance which is obtained by the union of two or more elements in the definite ratio by weight or it decomposes to give two or more elements (or compounds) whose properties are quite different from those of the compound.
Use of cardinal points.
Answer:- If cardinal points are known, one can find the image of any object without making a detailed study of the passage of the rays through the system i.e it is not necessary to consider the refraction of the rays at the various surfaces.
Henry's law.
Answer:- Mass of a gas dissolved per unit volume of a solvent is directly proportional to the pressure of the gas in equilibrium with the solution at a given temperature I.e C=KP. Where, P=partial pressure of the gaseous solute above the solution, C=concentration of dissolved solute & K=Henry's law constant.
What is zone plate ?
Answer:- A zone plate is a specially constructed screen such that light is obstructed from every alternate zone.It can be designed so as to cut off light due to the even numbered zones or that due to the odd numbered zones.
Spontaneous process.
Answer:- A process which can take place by itself without the assistance of an external agency under the given set of conditions is called a spontaneous process.
Coma or comatic aberration.
Answer:- The effect of rays from an object not situated on the axis of the lens results in an aberration called Coma or comatic aberration.In comatic aberration the image is comet-shaped & hence the name coma.
What is common ion effect ?
Answer:- The suppression of the degree of ionisation of a weak electrolyte by the addition of a strong electrolyte having an ion common with the weak electrolyte, is known as common ion effect.
Damped oscillation.
Answer:- When a body oscillates in the presence of resistive medium, then oscillation gradually die down & finally the amplitude becomes zero these oscillation called damped oscillation.
Chromatic aberration.
Answer:- When a parallel beam of white light is incident on a thin convex lens, then due to prismatic action of lens different colors are focused at different points on the principal axis.This phenomenon is called chromatic aberration.
Bond dissociation enthalpy.
Answer:- The amount of energy required to break one mole of bonds present between the atoms in the gaseous state is called the bond dissociation enthalpy.
Amagat law of partial volumes.
Answer:- This law states that; “When two or more gases which do not react chemically are enclosed in a vessel,then the total volume of the gaseous mixture is equal to the sum of the partial volumes, where partial volume of gas is the volume occupied by that gas at the same temperature and pressure of the mixture." Mathematically, V(mix)=V1+V2+V3+..........
Distortion.
Answer:- The variation in the magnification produced by a lens for different axial distances results in an aberration called distortion.
Moment of inertia.
Answer:- Moment of inertia of a body, about a given axis, is defined as the property of body by virtue of which it is unable to change its uniform rotational motion without the help of an external torque.
Hydrolysis of salts.
Answer:- Hydrolysis of salt is defined as the interaction of ions of a salt with oppositely charged ions of water to give acidic or basic solution.
Barrel shaped distortion.
Answer:- If magnification produced by lens decreases with increase in distance of object points from axis, then outer parts of image field of view are pulled inward such kind of aberration is called Barrel shaped aberration.
Absolute temperature.
Answer:- The temperature (hypothetical) at which all gases are supposed to occupy zero volume is called absolute temperature.
Marginal rays.
Answer:- Rays which are passing through a lens farther away from the axis are refracted more and come to focus closer to the lens are called marginal or peripheral rays.
Polybasic acid.
Answer:- There are many acids like oxalic acid, carbonic acid, sulphuric acid,phosphoric acid which contain more than one ionisable hydrogen.They have the ability to donate their protons successively.Such acids are called polybasic or polyprotic acids.
Pincushion distortion.
Answer:- If magnification produced by lens increases with increase in distance of object points from axis, then outer parts of image field of view are pulled outward such kind of aberration is called pincushion distortion.
Covalency.
Answer:- The number of valence electrons which an atom can share with electrons of other atoms to form covalent bonds is called its covalency.Covalency can also be defined as the number of covalent bonds made by an atom of the element with other atoms.
Monochromatic aberrations.
Answer:- The defects due to wide-angle incidence and marginal incidence of monochromatic light, are called monochromatic aberrations.It is again divided into five types★Spherical aberration ★Coma ★Astigmatism ★Curvature of field ★Distortion
Law of mass action.
Answer:- The rate at which a substance reacts is proportional to its active mass and rate of a chemical reaction is directly proportional to the product of the active masses of the reactants.
Compound pendulum.
Answer:- A pendulum which has distribution of mass inbetween the point of suspension and centre of gravity is called a compound pendulum.Compound pendulum may possess any shape regular or irregular.If the body is in the shape of a rectangular bar,The pendulum is known as a bar pendulum.Given figure is an example of bar pendulum,
Why a sheet of paper attracted by Tv screen ?
Answer:- TV screen is positively charged while due to ironed sheet of paper is negatively charged therefore coulombic force of attraction arise between them.
What is acid ?
Answer:- An acid is a substance (molecule or ion) which can accept a pair of electrons to form a co-ordinate bond.
Standard Gibb's energy change.
Answer:- The standard Gibb's energy change is defined as the Gibb's energy change for a process in which the reactants in their standard states are converted to the products in their standard states.
What is wave motion ?
Answer:- Wave is a disturbance which transfers energy or momentum from one location to another without transfer of mass.Such a mode of transfer of energy is called wave motion.
Lattice enthalpy.
Answer:- Lattice enthalpy of a compound is defined as the amount of energy released when one mole of the compound is formed due to electrostatic attraction between oppositely charged ions.
Resolving power.
Answer:- Resolving power of an optical instrument is defined as the ability of the instrument to see two objects as just separate.
Real gas.
Answer:- A gas which does not obey general gas equation and all other gas laws strictly but tends towards ideality at low pressure and high temperature is known as a real gas.
Impedance.
Answer:- Total effective opposition offered, by all the circuit elements in an a.c circuit is called impedance and is denoted by Z.
Transistor action.
Answer:- Transistor action is the term applied to the process of explaining the passage of electric current through a transistor.
Weak acids.
Answer:- Acids which dissociate to a small extent at ordinary dilution to give low concentration of H+ ion or H3O+ ion are called weak acids.
Triode.
Answer:- In order to improve the performance of a diode, another electrode in the form of a wire gauze cylinder was introduced in between the filament and the plate.This vacuum tube consisting of three elements namely plate, filament and grid is called a triode.
Half wave rectifier.
Answer:- A diode which translates only one half of the a.c input signal into output current is said to be acting as a half wave rectifier.
Full wave rectifier.
Answer:- A rectifier is said to be a full wave rectifier if it sends current, through the load, in one direction during both the halves of input a.c cycles.
Strong acids.
Answer:- Acids which dissociate almost completely in aqueous solutions thus producing a large number of H+ ions are called strong acids.e.g HCl,H2SO4 and HNO3 etc.
Electric potential due to a point charge.
Answer:- Electric potential, at any point, in an electric field is defined as the amount of work done in moving a unit positive charge between infinity to that point, without any acceleration, against the electric force.
Entropy of sublimation.
Answer:- It is the entropy change when 1 mole of a solid changes into vapour at a particular temperature.
Thin lens.
Answer:- A lens is said to be thin if the thickness of the lens can be neglected when compared to the lengths of the radii of curvature of its two refracting surfaces, and to the distances of the objects and images from it.
Gravitational waves.
Answer:- It is suggested that the cosmic bodies such as galaxies, stars produce gravitational waves and interact with each other through these waves.The gravitational waves are believed to propagate with the velocity of light.
Conditions of interference.
Answer:- ★The two sources should emit continuously waves of same wavelength or frequency. ★The amplitudes of two waves should be equal or nearly equal. ★The two sources should be narrow. ★The two sources should be placed closed to eachother. ★The two sources should be coherent (i.e their is no phase difference or having constant phase difference between two waves.
Coherence time.
Answer:- It is the average time during which the wave remains sinusoidal and phase of the wave packet can be predicted reliably.
Ideal gas.
Answer:- A gas which obeys the general gas equation and other gas laws under all conditions of temperature and pressure is known as ideal gas or perfect gas.
Gauss's law in electrostatics.
Answer:- It states that for any distribution of charges the total flux linked with a closed surface is equal to 1/ ε0 times total charge enclosed with in the surface.
Graham's law of diffusion.
Answer:- Under similar conditions of temperature and pressure, the rates of diffusion of gases are inversely proportional to the square root of their densities.
Fraunhofer diffraction.
Answer:- The conditions required for Fraunhofer diffraction are achieved using two convex lenses, one to make the light from the source parallel & the other to focus the light after diffraction to the slit.
Avogadro's law.
Answer:- It states that equal volumes of all gases contain equal number of molecules under similar conditions of temperature and pressure.
Why two electric lines of force never intersect eachother ?
Answer:- Two lines of force never intersect eachother because if they intersect eachother then two tangents could be drawn at that point.This means their could be two directions of electric field which is impossible.
Gay-Lussac's law.
Statement:- It states that at constant volume, the pressure of a given mass of a gas increases by 1/273 of its original pressure at 0⁰C for every 1⁰C rise in temperature.
Fresnel diffraction.
Answer:- In this type of diffraction, the source of light and the screen are effectively at finite distances from the obstacle.Observation of Fresnel diffraction phenomenon does not require any lenses. Examples are (I) Diffraction at rectangular slit (II) Diffraction at circular aperture