TyroCity: Physics XII Notes

Diffraction

Physics XII Notes — Sat, 12 Jul 2014 05:41:42 +0000

Diffraction grating is better than a two –slit set up for measuring the wave length of monochromic light. Explain.
What is diffraction of light?
Radio waves diffract around building but light waves do not. Why?
The diffraction of sound waves is more evident in daily experience than that of light waves, why?
Describe what happens to the single slit diffraction pattern when the width of the slit is less than the wave length of the wave.
What is self-inductance? Define coefficient of self-inductance.
What is diffraction of light? How does it differ from interference of light?
Describe the diffraction of light at a single slit and find the condition for secondary maxima and minima.
What are the difference between interference and diffraction? Explain the theory of diffraction off light through a single slit.
Describe diffraction of light through a single slit.
What is the basic difference between interference and diffraction? Discuss Fraunhofer diffraction at a single slit.
What is Fraunhoffer diffraction? Explain the formation of maxima and minima due to diffraction? Show that the width of central maxima is inversely proportional to the distance between the two slits.

Polarization

Physics XII Notes — Sat, 12 Jul 2014 05:41:42 +0000

Short answers question

Can sounds waves be polarized? Explain.
Is polarization possible for longitudinal waves? Why?
Light waves can be polarized. What about sound waves? Explain.
What is polarizing angle? Does it depend on the wavelength of light?
The polarizing angle for a transparent medium is 600. What is the refractive index of the medium?

Long answers question

Distinguish between a plane polarized and unpolarized light.
Show that: tan p=n
Where
n=refractive index of the medium
p=angle op polarization of polarizing angle.
What do you mean by polarization of electromagnetic waves? Discuss the polarization of light by refection and show that , where the symbols have their usual meanings.
What is polarizing angle? Derive the relation between the polarizing angle and the refractive index of the medium.

Alternating Currents

Physics XII Notes — Sat, 12 Jul 2014 05:41:42 +0000

Short Questions

Why do we prefer a choke coil to rheostat in an a.c. current?
What is meant buy independence of an a.c. current?
Why is choke coil preferable to resistor?
Why is choke considered superior to a rheostat?
What do you mean by r.m.s value of an AC current?
What is meant by wattles current?
Fluorescent tubes often use an inductor to limit the current through the tube. Why is it better to use inductor than a resistor for this purpose?
Why is a choke coil better than a resistor ina n electrical appliences?
Define rms value of alternating current.
What are the advantages of a.c. over d.c.?
A chock coil is preferred to a resistor in an ac current. Why?

Long Questions

Discuss the phase relationship between the voltage and current in the ac current containing inductance and resistance. What is power factor of the circuit?
Find the impendence of LCR circuit in series.
An alternating emf is applied across a capacitor. Show that the current in its leads to the applied emf by 90°.
An a.c. passes through a circuit containing a resistor and a inductor in series. Derive an expression for the phase relation between the current and the voltage.
Discuss the phase relationship between the voltage and current in the a.c. circuit containing capacitor and resistor in series and hence derive an expression for the impedance of the circuit.
Derive the condition for resonant frequency of an LCR alternating current series circuit.
Derive an expression of current flowing through a.c. circuit containing a resistor and capacitor in series combination. What is the power factor of this circuit?
Discuss the phase relationship between the circuit and voltage in a.c. circuit containing capacitor and resistor in series and hence derive an expression for the impedance of the circuit.

Free question test - Physics 12

Physics XII Notes — Sat, 12 Jul 2014 05:41:42 +0000

Current Electricity

Discuss the mechanism of metallic conduction. Derive a relation between current density and drift velocity.
How is a galvanometer converted into an ammeter and to voltmeter? Explain?
Distinguish between resistance and resistivity. Derive expression for the effective resistance of number of resistors, connected in series and parallel.
Wave and Sound
What is resonance? How is the velocity of sound in air determined by resonance tube method?
What is the principle of super position as applied to wave motion? Discuss, the result of superposing two waves of equal amplitude and same frequency travelling in opposite direction.
What do you mean by phase oscillation and phase constant? Establish the equation of progressive wave.
Magnetic Effect if Current
Define radial magnetic field. Derive an expression for the torque on a rectangular coil in a uniform magnetic field and mention the condition for maximum and minimum torque.
Derive an expression for the magnetic field intensity at a point due to a current carrying straight conductor of infinity length, using Biot-Savart law.
Obtain an expression for the torque acting on a rectangular coil in a uniform magnetic field and also define magnetic moment.

Modern Physics

Describe J.J. Thomson’s experiment for determining the specific charge of an electron.
Describe the phenomenon of electrical discharge through gases.
Describe with necessary theory of Millikan’s oil drop experiment to determine the value of the charge particle in electric and magnetic field.
Discuss the productivity of cathode ray and its characteristics.

Thermoelectric Effect

Physics XII Notes — Sat, 12 Jul 2014 05:41:42 +0000

Short Questions

What do you mean by Peltier`s effect?
What is thermoelectric emf?
Why is Sb-Bi thermocouple preferred to Fe-Cu thermocouple?
What are the factors on which the thermo emf produced in a thermocouple depends?
How is Seebeck effect different from Pektier effect? Explain.
How does thermo emf change in thermocouple when the temperature of the hot junction is changed?
What are the factor on which thermo-emf depend?
Define temperature of inversion. On what factors does it depend?
What do you mean by thermoelectric effect?
Does the thermo-electric effect obey the Law of conservation of energy? Explain.

Long Questions

What do you mean by Seebeck Effect? How thermoelectric e.m.f. does vary with the temperature?
What is Seebeck Effect? How does the emf of a thermocouple vary with temperature of the hot junction?
How does the thermo efm of a thermocouple vary with temperature of the hot junction?
What is thermoelectric effect? Discuss the variation of thermo-efm with the change in temperature of the hot junction.

Interference

Physics XII Notes — Sat, 12 Jul 2014 05:41:42 +0000

Short Answer Questions

Can two independent sources of light produce interference?
Why have the two sources of light to be close to each other for the production of good interference pattern?
Distinguish between interference and diffraction. What do you understand by coherent sources?
In young’s double slit experiment, how is the fringe width altered if the separation between the slits is doubled and the distance between the slits and the screen is halved?
What are the conditions for sustained interference of light?
In Young’s double slit experiment, how is the fringe width altered if the separation between the slits is doubled and the distance between the slits and the screen is halved?
What do you understand by the coherent sources of light?

Long Answer Questions

Derive the fringe width from Young’s double slit experiment.
What do you understand by interference of light? Derive an expression for the fringe width in a Young’s double slits experiment.
Describe Young’s double slits experiment for the interference of light and show that widths of bright and dark fringes are the same.
Prove analytically that the bright and dark fringes in young’s double slit experiment are equally spaced.
Draw a clear ray diagram to illustrate the action of a compound microscope. Also derive an expression for its magnifying power.
Describe Young’s double slit experiment, if brief, for the measurement of wave=length of a monochromatic source of light.
Where is the near point of an eye for which a spectacle lens of power +2D is prescribed?

Chemical Effect Of Current

Physics XII Notes — Sat, 12 Jul 2014 05:41:42 +0000

Short Questions

What is meant by Faraday’s Constant?
What is the function of copper sulphate used in Daniel cell?
Define one Faraday?
Distinguish between ionic and electronic conduction.

Long Questions

State and explain Faraday’s law of electrolysis. Hence, define Faraday’s Constant.
State the Faraday’s laws of electrolysis and verify the second laws.
State Faraday’s law of electrolysis. Discuss the experiment to verify them.

Mechanical Waves

Physics XII Notes — Sat, 12 Jul 2014 05:41:42 +0000

Short

Why sound made/produced at a distance can be heard distinctly at night than in the day time?
Is velocity of sound more in damp air or in dry day?

3.Why sounds are heard better on a wet day than on a dry day?

Do sound waves need a medium to travel from one point to other point in space? What properties of the medium are relevant?
Although the density of solid is high, the velocity of sound is great in solid, explain.
Explain why the velocity of sound in solids is greater than that in gases, though the densities of solids are greater than that of gases.
Sound at distances can be heard distinctly at night than in the day time. Why?
Velocity of sound increases on a cloudy day. Why?
Sound travels faster in metal than in air, why?
Can two persons on hear the sound of each other? Explain.

Long

Discuss the effect of pressure, temperature and density of elastic medium on the velocity of sound.
What is Newton`s formula for the velocity of sound? What correction was made by Laplace?
Describe Newton`s expression for the velocity of sound in a gas.
Derive an expression for the velocity of sound in a medium by dimensional method. Discuss the effect of change in pressure and temperature on the velocity of sound in air.
Discuss Laplace`s correction and derive the formula for the velocity of sound in a gas.
State Newton`s formula for the velocity sound in gases. What correction was done by Laplace on it?
Explain the significance of Laplaces correction of Newtons formula for the velocity of sound derive the corrected formula.
Write down the factors on which the velocity of sound in air depends with necessary explanation.
Discuss Newtons formula for the velocity of sound in a gas with Laplaces correction.
Discuss Newtons formula for the velocity of sound in air with Laplaces correction.
Write an expression for the speed of sound in an ideal gas. Discuss the effect of change in temperature on the speed of sound.

Electromagnetic Induction

Physics XII Notes — Sat, 12 Jul 2014 05:41:42 +0000

Short Questions

What is Lenz’s law?
Mention two types of loss in a transformer.
Show that Lenz’s law is an example of conservation of energy.
Two closely would circular coils have the same number of turns, but one has twice the radius of the other. What is the ratio of self inductance’s of the two coils?
Why can`t a transformer be used to change the value of d.c. voltage?
What is eddy current? Write down its uses?
What are different power losses in a transformer? What measures do you take to minimize these losses?
Why can`t a transformer be used to step up or down the d.c. voltage?
A transformer cannot be used in do circuits, why?
State Faraday`s laws of electromagnetic induction.
A sheet of copper is placed between the poles of an electromagnet with the magnetic field perpendicular to the sheet. When it is pulled out, a considerable force is required, and the force required increases with speed, why?
Permanent magnets are made of steel while the core of transformer is made of soft iron. Why?
A student asserted that if a permanent magnet is dropped down a vertical copper pipe, it eventually reaches a terminal velocity even if there is no air resistance. Why should this be?
If a permanent magnet is dropped down a vertical copper pipe, it eventually reaches a terminal velocity even if there is no air resistance. Why should this be?
Describe the theory and working of an a.c. generator.

Long Questions

Obtain the expression for the emf induced in the conductor moving in a magnetic field.
State the laws of electromagnetic induction. Derive an expression for the emf induced in a conductor moving in a magnetic field.
Deduce an expression for induced emf in a coil rotating in a magnetic field.
State Lenz`s law and explain how this law leads to the conservation of energy principle.
State Faraday`s laws of electromagnetic induction. Deduce an expression for induced emf in a coil rotating in a magnetic field.
State and explain Faraday`s law of electromagnetic induction. Derive an expression for the induction a coil rotating in a uniform magnetic field.
State Faraday`s law of electromagnetic induction. Derive an expression for the induced in a straight conductor moving at right angle to the direction of a uniform magnetic field.
A metallic rod is moving in a magnetic field. Determine the emf induced across it.

Nature and Propagation of Light

Physics XII Notes — Sat, 12 Jul 2014 05:41:42 +0000

Short

Differentiate between a plane wave front and a spherical wave front.
Which parameter of light does not change on refraction?
Define accommodation of eye and its near point.
What is Huygens principle?
When monochromatic light incidents on a surface, the reflected and refracted wave will have same frequency. Why?
State Huygens principle. Does it apply to sound waves in air?
What is a wave front?

Long

State and explain Huygens principle. Use the principle to show that a plane wave front incident obliquely on a plane mirror is reflected as a plane wave front so that angle of incidence is equal to the angle of reflection.
Prove the law of reflection of light using the wave theory?
Define Huygen’s principle and prove Snell’s law by the help of wave theory of light. State and explain Huygen’s principle. Use the principle to show that a plane wave front incident obliquely on a plane reflecting surface is reflected as a plane wave front so that the angle of incidence is equal to the angle of reflection.
Describe Michelson’s method for the determination of speed of light. Write advantages of the method over Foucault’s method.
State and explain Huygen’s principle. Use the principle to show that a p lane wave incident obliquely on a plane mirror is reflected as a plane wave so that the angle of incidence is equal to the angle of reflection.
Describe Foucault’s method for the determination of speed of light.

Mechanical Waves: Important Questions

Physics XII Notes — Sat, 12 Jul 2014 05:41:42 +0000

What do you mean by water waves?
Why sound produced at a distance can be heard distinctly at night than in day time?
Is velocity of sound more in damp air or in dry air? Explain.
A boat at anchor is rocked by waves whose crest is 100 feet apart and whose velocity is 25 feet /s. These reach the boats once in every t s. What is the value of t?
Ultrasonic, infrasonic and audio waves travel through a medium with velocity vu, vi, varespectively. Then what is the relationship among them?
A man stands on the ground at a fixed distance from a siren whit emits a sound of fixed amplitude.
The ratio of velocity of sound in hydrogen gas r=7/5 to that on helium gas r= 5/3 at the same temperature is VH:VHe, what is the value of this ratio?
The velocity of sound in a tube containing air at 27°C at the pressure of 760 cm of Hg is 330 m/s. What will be the velocity of sound when the pressure is increased to 100 cm of Hg and temperature is kept constant?
A uniform rod of length L and mass M hangs freely from a fined point. Then the velocity of transverse wave along the rod at a distance x from the free end is v m/s. What is its value?
In a ripple tank when one pulse is sent every 10th of a second, the distance between consecutive pulses is 30 mm. in the same depth of water pulse are produced in half second intervals. What is the distance between consecutive pulses?
If you are walking on the moon surface, can you hear the cracking sound behind you? Explain.
Do sound waves need a medium to travel from one point to other point in space? What properties of the medium are relevant?
Why velocity of sound in solid is more than that in liquid?
Why velocity of sound in liquid is more than that in air?
Why velocity of sound in hydrogen is more than that in air?
What are the draw backs of Newton’s formula for the velocity of sound in air? What is the Laplace’s correction?
What is the sound of clock tower heard feebly at large distance than near to it?
What is beat? How a musician can use this effect to tune string instrument?
What is threshold of hearing and threshold of pain?
Why are beats produced? What is beat frequency?
What is it that one can recognize a friend from his voice without seeing him?
Whistle of an approaching train is shriller. Why?
Although the density of solid is high, the velocity of sound is greater in solid, explain.
Why is roaring of the lion different than that of mosquito?
What is persistence of hearing? Also define threshold of hearing (or audibility) threshold.
Why is the wall at the back of the stage in a big hall made parabolic?
A stone is dropped from the top of the tower 300m high splashes into the water of a pond near the base, of the tower. When is the splash heard at the top? Given that the speed of sound in air is 340 m/s, g= 9.8 m/s [ ans= 8.70 s]
The audible frequency range of a human air is 20Hz to 20KHz. Convert this into the corresponding wavelength range. V of sound on air = 340 m/s.
Draw the graph for beat phenomenon.

Electrical Circuits

Physics XII Notes — Sat, 12 Jul 2014 05:41:42 +0000

Short Questions

State Kirchhoff`s laws of circuits.
Why does voltmeter measures current more accurately than an ammeter?
What is Wheatstone bridge? Obtain the balanced condition for the bridge? Explain how resistance can be measured by a meter bridge?

Long Questions

What is a Wheatstone bridge? Using Kirchhoff`s law, derive the principle of Wheatstone bridge.
What is a potentiometer? Explain how you compare the emfs of two cells using a potentiometer.
Discuss the principle of potentiometer and use it to determine the internal resistance of a cell.
Discuss the principle of the potentiometer and use it to compare the emfs of two cells.
Explain the principle of the potentiometer. How is this used to measure the internal resistance of a cell?
State and explain Joule`s law of heating. Deduce an expression for the heat developed in a wire by the passage of an electric current?
What is potentiometer? How can you use it to measure internal resistance of a cell?
What is internal resistance of a cell? How can you measure the internal resistance of a cell by using potentiometer?
What is the principle of potentiometer? Describe a method to measure the internal resistance of a cell by using potentiometer.
What is Wheatstone bridge? Derive the principle of Wheatstone bridge using Kirchhoff`s Law.