Practice Questions(short type) Of Physics for 12th Board Exam
1. How is energy lost in sharing of charge between conductors?
2. Define dielectric strength and relative permittivity.
3. Why pointed portion is not left in an electrostatic machine?
4. State principle of superposition for electric forces?
5. Is mass of a body changed when it is charged?
6. Write limitations of coulomb’s low.
6. Deduce coulomb’s law from Gauss theorem.
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7. Find out the expression of torque on an eclectic dipole in an external
electric field and its energy.
8. Describe the series and parallel combination of capacitors.
9. Define electric dipole moment.
10.
Obtain the expression for energy
of a charged conductor (or capacitor).
11.
Electric field lines do not
intersect each-other why?
12.
What do you mean by quantisation
of charge? (or law of conservation of charge)
13.
What is importance of writing coulomb force in vector form?
14.
Write two properties of electric
charge.
15.
What is electrostatic shielding?
16.
Derive E=-dv/dr
17.
What is equip-potential surface?
Prove that electric field is perpendicular to equipotential surface.
18.
What are polar and non-polar
dielectrics?state polarisation of a dielectric?
2. CURRENT ELECTRIC
1. State the colour coding of carbon resistors.
2. Define drift velocity, mobility and current density.
3. State seebeck and peltier effect.
4. What is resistivity? Write its S.I. unit. State the variation in resistivity of a semiconductor with temperature.
5. If an student connect a voltmeter in series and an ammeter in parallel
by mistake. Then what will happen.
5. What is wheat-stone bridge ? Explain its use in detail .
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6. In wheat-stone bridge galvanometer key is switched on after battery key
why?
7. What do you mean by super conductivity?
8. Coils of a resistance box are made of doubled wire. Why?
3. MAGNETIC EFFECT OF CURRENT & MAGNETISM
1. How does a current carrying solenoid behave like a bar magnet?
1. Explain behavior of a current loop as a magnetic dipole.
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2. What is shunt? How will you convert a galvanometer into voltmeter and ammeter?
3. Why poles pieces of magnet used in moving coil galvanometer are cylindrical in shape?
4. Why steel is used in making permanent magnet while soft iron is used in making electromagnet?
5. Write curie’s law.
6. State elements of earth magnetism.
7. What is magnetic hysteresis and coercive force?
8. What is Lorentz force?
9. What are neutral points?
10. Define-
(a) permeability
(b) magnetic meridian
(c) Intensity of magnetization
(d) Intensity of magnetizing field
(e) Magnetic susceptibility
(f) Magnetic retentivity
(h) Mariner’s compass
(i) Bohr magneton
(j) Magnetic map
(k) Magnetic storm
(l) Fleming’s left (or right) hand rule
11.Obtain expression for torque (or energy or work) on a bar-magnet (or magnetism dipole in uniform magnetic field.
12. State magnetic dipole moment of a current carrying loop.
4. ELECTROMAGNETIC INDUCTION & ALTERNATING CURRENT
1. What are eddy currents? Write their uses.
2. Lenz’s law follows the law of conservation of energy. How?
3. In resistance box resistance coil is made by doubled wire. Why?
4. What is choke coil?
5. Core of a transformer is laminated. Why?
6. State the loss of energy in a transformer.
7. What do you mean by resonant circuit and resonant frequency?
8. Define inductive reactance, capacitive reactance and impedance.
9. What is L-C oscillation?
10. Hot wire instrument is used to measure Ac. Why?
11. What do you mean by power co-efficient?
12. What is electric power? Obtain expression for average power. 5. ELECTROMAGNETIC WAVES
1. Write expressions for electric energy density and magnetic energy density
and show that their ratio is 1.
2. Write four main properties of electromagnetic waves.
3. What is electromagnetic spectrum?
4. What is displacement current?
5.State ampere-Maxwell law .
1. What is polarisation of light? State brewster's law.
2. What is Polaroid ?write its uses.
3. What is optical fiber? Write its uses.
4. What is refractive index? How is it related to critical angle?
5. What are necessary conditions for obtaining pure spectrum?
6. Write necessary conditions for interference of light.
7. State difference between magnification and power of magnification.
8. How is chromatic aberration reduced?
9. Why does the aperture of objective of a compound microscope (or of a
telescope) is kept small (or big)?
10.
How does the focal length of a
lens get changed when dipped in a liquid?
11.
Why does the morning or evening
sun appear red?
12.
Explain the blue colour of sky?
13.
Write malus law of polarisation.
14.
Interference fringes are not
formed by two independent sources. Why?
15.
Explain the condition to obtain pure spectrum.
16.
What is retinal fatigue?
17.
Write difference between primary
and secondary rainbow.
18. Diamond is brighter than ordinary glass. Why?
19. What is persistence of vision?
20. How is the velocity of light detected by nature of medium?
21. Write difference between interference and diffraction.
22. Define-
(a) Spectrometer
(b) scattering of light
(c) minimum deviation of a prism
(d) Dispersive power
(e) Difference between reflecting and refracting telescope.
(f) Distortion in a lens. (g) Difference between emission and absorption spectrum.
(a) Spectrometer
(b) scattering of light
(c) minimum deviation of a prism
(d) Dispersive power
(e) Difference between reflecting and refracting telescope.
(f) Distortion in a lens. (g) Difference between emission and absorption spectrum.
(h)Exemplify interference of light in nature
7. DUAL NATURE OF MATTER AND RADIATION
1. What do you mean by debrogli wave? Write formula for its wave-length.
2. Define threshold frequency, work-function and stopping potential.
3. Thermionic emission only occurs on metal surface. why?
4. Show that debrogli wave length of an electron with kinetic energy E
will be
5. What do you mean by photo electric effect
6. Photo electric current is directly proportional to intensity of light
but maximum velocity of photo electrons does not depend upon intensity of
light. Explain.
8. ATOM & NUCLEUS
1. What do you mean by critical mass (or critical size)?
2. What is carbon dating?
3. Write the properties of α, β, γ rays.
4. What is atomic piling?
5. Write two demerits of rutherford atomic model.
6. What is source of solar energy?
7. What do you mean by nuclear fusion and nuclear fission?
8. Plot Yukawa potential graph.
9. Is coulomb's law true for atomic distances?
10.
How is the size of an atom
related to mass-number?
11.Define half-life, decay constant, radioactivity
and obtain relation between half-life time and decay-constant12. Explain constitution of atomic nucleus .
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14. Define haft life time and average life time.
9. ELECTRONIC DEVICES
10. COMMUNICATION SYSTEM
13. Write difference between nuclear fission and radioactivity .
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14. Define haft life time and average life time.
9. ELECTRONIC DEVICES
1. Explain (ii) zener diode (ii) LED (Light Emitting Diode)
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2. p-n junction is a valve .Explain .
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2. What do you mean by doping?
3. Write the truth table of NAND (or NOR) gate.
4. Write difference between p-type and n type semiconductor.
5. What are intrinsic and extrinsic semiconductors?
6. Diode is called valve. Why?
7.Define Valence band, conduction bond and forbidden gap?
8. N-p-n transistors are used more than p-n-p transistors why?
9. What is effect of temperature on resistivity of a semiconductor?
10. What is oscillator?
10. COMMUNICATION SYSTEM
1. Write properties of LASER.
2. What are the main parts of communication system?
3. What is Ionosphere?
4. What is green house effect?
5. What is E-commerce?
6. What is amplitude modulation index?
7. Satellite is necessary for long distance T.V. transmission. Why?
8. Define antenna, remote sensing and modem.
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