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In this article I Share the 12th Class Physics Guess Paper Important Short and Long Questions PDF Download. This Guess Paper for 12th Class Part 2 for Urdu Books 2021 is a fresh Guess Paper for the Students.
NOTE: Physics Guess Paper is for all Punjab Boards. This guess paper is for Lahore board, Gujranwala Board, Rawalpindi Board, Multan Board, Bahawalpur Board, Sahiwal Board etc.
12th Class Physics Guess Paper 2021
2nd Year Physics Important MCQs With answer Keys
- 12th Class Physics MCQs Guess Paper 2021 (Important MCQs)
2nd Year Physics Important Short Questions and Long Questions
2nd Year Physics Important Short Questions
Why are heavy nuclei unstable?
A particle which produces more ionization is less penetrating. Why?
What factors make a fusion reaction difficult to achieve?
Give two uses of radioactivity in medicine.
What is meant by background radiations? Give its sources.
Distinguish between nucleon number and atomic number.
What is meant by half-life?
Describe a brief account of interaction of various types of radiations with matter.
Is energy conserved when an atom emits a photon of light?
What do we mean when we say that the atom is excited?
What are the advantages of laser over ordinary light?
What is the speed of an electron in the first Bohr orbit?
Give characteristics of X-rays.
What is meant by spontaneous emission?
Explain why laser action could not occur without population inversion between atomic levels.
16. Define the following: a. Band spectra b. Line spectra c. Spectroscopy
We do not notice he de Broglie wavelength for a pitched cricket ball. Explain why?
When does light behave as a wave? When does it behave as a particle?
What is threshold frequency?
Is it possible to create a single electron from energy?
What are the advantages of an electron microscope over an optical microscope?
What is the minimum energy required to eject an electron from the metal surface?
What is meant by inertial and non inertial frames of reference?
Why don’t we observe the Compton Effect with visible light?
What is uncertainty principle
What is the net charge on an n-type or p-type substance?
Why ordinary silicone diodes do not emit light?
Distinguish between intrinsic and extrinsic semiconductor.
Why is the base current in a transistor very small?
Calculate the output of the op-amp circuit shown in the figure.
Define rectification and draw a circuit diagram for half wave rectifier.
The inputs of a gate are 1 and 0. Identify the gate is its output is (a) 0, (b) 1.
What is an operational amplifier? Give its characteristics.
What is meant by forward biased and reverse biased?
Distinguish between polymeric, crystalline and amorphous solids.
What is meant by strain energy? How can it be determined from the force-extension graph?
37. Define the following: (i) strain (ii) stress (iii) superconductor.
38. What is meant by para, dia and ferromagnetic substances? Give example of each.
39. A 1.5 cm diameter cylinder is subjected to a load of 2500 kg. Calculate the stress on the bar in mega Pascal.
40. Differentiate between intrinsic and extrinsic semiconductors. How will you obtain n-type and p-type semiconductors from silicon?
41. What is meant by hysteresis loss? How is it used in the construction of a transformer?
42. What is meant by compressive deformation?
43. Define modulus elasticity.
44. Why D.C cannot flow through a capacitor?
45.What is meant by A.M and F.M?
46. Define the following: (i) inductor (ii) choke (iii) impedance.
47. How does doubling the frequency affect the working of inductor and capacitor?
48. Differentiate between amplitude modulation and frequency modulation.
49. When 10 V is applied to an A.C circuit the current flowing in it is 100 mA. Find its impedance.
50. In A.C the power P= I2R= VI= in what circumstances it hold true?
51. What is the main advantage of three phase supply?
52. How many times per second will an incandescent lamp reach maximum brilliance when 53. connected to 50 Hz source?
54. Define lenz’s law and give its expression.
55. Define motional emf and give its expression.
56. Show that the have the same units.
57. Can a D.C motor be turned into D.C generator? How?
58. Write the cause of power dissipation in transformers.
59. Define self induction and mutual induction. Give their units.
60. How efficiency of a transformer can be improved?
61. What is the relation between back emf of motors and current?
62. Why the motor draws more current when it is overloaded?
63. How the electron beam is generated in CRO?
64. Why does the picture on a TV screen become distorted when a magnet is brought near it?
65. Why the charge particle is projected to the perpendicular to the magnetic field?
66. What is deflecting couple? How is it used?
67. A charge particle moves in a straight line through some region of space, is the magnetic field in region zero?
78. Give two functions of AVO meter?
69. Why the resistance of ammeter should be very low?
70. What is the current sensitivity of a galvanometer?
71. What is shunt resistance?
72. Do bends in a wire affect its electrical resistance?
73. What is drift velocity?
74. Why potentiometer is an accurate measuring instrument?
75. What is the principle of Wheatstone bridge?
76. What are the negative coefficients of temperature?
77. Why does the resistance of a conductor rise with temperature?
78. Describe the circuit which will give continuously varying current.
79. Why the resistance of voltmeter should be high?
80. Write the difference between emf and potential difference.
81. State Coulomb’s Law.
82. Write the properties of electric field lines.
83. What is a capacitor? Also define capacitance and its SI unit.
84. Define electron volt and electric potential.
85. Electric lines of forces never cross. Why?
86. State Gauss’s law and give its expression.
87. Write two differences between gravitational force and Coulomb’s electrostatic force.
88. How can you identify which plate of capacitor is positively charged?
2nd Year Physics Important Long Questions
- What is electric field? Find the electric field intensity due to an infinite sheet of charge.
- Find electric potential at a point due to a point charge
- Write a note on Wheatstone bridge.
- Define electric power. Derive an expression for the power dissipated in a resistor.
- What is voltmeter? How galvanometer is converted into voltmeter?
- A power line 100m high carries a current 200A. Find the magnetic field of the wire at the ground.
- A solenoid 15.0 cm long has 300 turns of wire. A current of 5.0A flows through it. What is the magnitude of magnetic field inside the solenoid?
- Describe the principle, construction and working of a galvanometer.
- An ideal stepdown transformer is connected to main supply of 240 v. It is desired to operate a 12v, 30 watt lamp. Find the current in the primary and transformational ratio.
- Describe the principle, construction and working of a D.C generator.
- A solenoid has 250 turns and its self inductance is 204 mH. What is the flux through each turn when the current is 2 A. What is the induced emf when current changes at 20 A s-1?
- Derive and expression for the energy stored in an inductor and also for the energy density.
- Find the value of the current flowing through a capacitance 0.5 uF when connected to a source
- of 150 V at 50 Hz.
- Describe A.C through and inductor.
- Describe series and parallel resonance circuits?
- A 1.0 m copper wire is subjected to stretching force and its length increases by 20 cm. Calculate the tensile strain and the percent elongation which the wire undergoes.
- Explain the magnetic properties of solids.
- Explain the mechanical properties of solids?
- What are semi-conductors? Discuss the formation of P-type and N-type materials with diagram.
- What is operational amplifier? Discuss operational amplifier as inverting amplifier. Calculate its gain.
- Calculate the gain of an amplifier in which collector resistance RC is 5kΩ. The input resistance between the bas and emitter of a typical resistor is 2.5 kΩ and value of its β = 100.
- Discuss the structure and working of electron microscope.
- Write a note on photoelectric effect.
- What is the mass of a 70 kg man in a space rocket travelling at 0.8 C from us as measured from the earth?
- An electron is accelerated through a potential difference of 50 V. Calculate de Broglie wavelengths.
- What the energies in eV of quanta of wavelength? ƛ = 400, 500, 700 nm.
- Describe Bohr’s postulates of hydrogen atom.
- Give the uses of laser in medicine and industry.
- Explain the working principle of laser.
- Define isotopes and describe mass spectrograph to separate different isotopes of an element.
- Radiations from a point obey the inverse square law. If the count rate at a distance of 1.0 m from Geiger counter is 360 counts per minute, what will be its count rate at 3.0 meter from the source?
- Describe Wilson cloud chamber to detect radiation.
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