Physics XII Karachi Board Fill in the Blanks

Five Year Papers

1. If a liquid contracts on freezing, an increase of pressure __________ the freezing point.

2. The flux through a surface is maximum, when the angle between E and A is __________.

3. An electron volt = __________ joules.

4. Uit of Electric intensity in S.I system is __________.

5. __________ is the unit of mutual-inductance.

6. Back e.m.f is the effect of self-inductance in a coil when __________ current passes.

7. From the theory of relativity the velocity of light is a __________ constant and is equal to __________m/s.

8. The amount of heat, which is absorbed during the change of state without the rise in temperature, is known as __________.

9. If heat energy is removed from the system, the change in entropy is __________.

10. The flux through a closed surface, which does not contain any charge, is __________.

11. The electric field at any point between two oppositely charged plain sheet is __________.

12. __________ is the unit of physical quantity, Magnetic Induction B.

13. If a one-metre long wire is placed perpendicularly in a magnetic field of value 5mT, the force it experiences is equal to 5N.

14. The value of the permitivity of free space is given by __________.

15. The minimum energy required to excite a hydrogen atom is __________.

16. During the change of state, the heat supplied does not change the temperature. It is used in __________.

17. The flux through a surface is maximum when the angle between E and DA is __________.

18. The resistivity of a material of a conductor increases due to increase in __________.

19. Back e.m.f is the effect of self-inductance in a coil when a __________ current passes through it.

20. The frequency of the incident light at which the photons have energy equal to the work function of a metal is called the __________ of that metal.

21. When temperature of source and sink of a heat engine becomes equal, the entropy change will be __________.

22. Quantity of heat in a body depends upon its mass temperature and __________.

23. Electric flux through any closed surface due to point charges enclosed in it is equal to __________.

24. The __________ in the free electron is responsible for generation of current in the wire.

25. Units of electrical energy commonly used is __________.

26. A balanced __________ is used to determine an unknown resistance.

27. Nuclei of same element with different nuclear masses but the same charge number are called __________.

28. Radiations with wavelength greter than red light are called __________ radiations.

29. The galvanometer can be made sensitive if the value of the factor C/BNA is __________.

30. A particle with mass equal to an electron but charge that of proton is called __________.

Chapter 11

Heat

1. Mathematically Boyle’s Law is stated as __________.

2. Mathematically Charle’s Law is stated as __________.

3. Absolute Zero of the temperature is __________.

4. The gas in which the molecules exert no force on each other is called __________.

5. In an ideal gas the molecules have __________.

6. Most of the gases with low density and well above the liquefication temperature behave as __________.

7. “At constant pressure and temperature the number of kilomoles of any gas is proportional to the volume of the gas.” This is called __________.

8. General gas law is mathematically stated as __________.

9. General gas law or general gas equation is derived from __________, __________, and __________.

10. The value of universal gas constant R is given by __________.

11. The pressure of an ideal gas is given by the following equation __________.

12. In terms of average kinetic energy of the molecules of the gas, the pressure of an ideal gas is given as __________.

13. “Equal volumes of gases at the same temperature and pressure contain equal number of molecules.” This is called __________.

14. The change in length per unit length per Kelvin rise in temperature is called __________.

15. Mathematically co-efficient linear expansion is written as __________.

16. Coefficient of cubical expansion in terms of co-efficient of linear expansion is written as __________.

17. The amount of heat required to raise the temperature of 1.0kg of a substance through 1k is called __________.

18. The study of relationship between heat and other forms of energy is called __________.

19. Any object or set of objects that we wish to consider is called __________.

20. Every thing other than the system is termed as __________.

21. A system in which the mass of the system remains constant is called a __________.

22. The variables like p, V and t are called __________.

23. The process in which the state variables acquire the same values at all stages of the process independent of the direction in which the process is being carried out is called __________.

24. A cyclic process is that in which during each cycle, it extracts heat from a heat reservoir maintained at one temperature, converts part of this energy to useful work and rejects the remainder to a heat reservoir at a lower temperature is called __________.

25. The ratio of net output work per cycle to input energy per cycle is called __________.

26. A cycle that has highest possible efficiency is called __________.

27. Efficiency of a Carnot Engine is defined as __________.

28. “Heat flows spontaneously from a hotter to a colder body, but not the other way round.” This is called __________.

29. “It is impossible for a cyclic system to transfer heat from body at a low temperature to a body at a higher temperature unles external work is done on system." This is __________.

30. It is impossible to construct an engine, operating continuously in a cycle, which does nothing other than to take heat from a source and perform an equivalent amount of work without having a sink.” This is __________.

31. A heat engine operating in reverse is called __________.

32. A device, which causes heat to flow from a low temperature reservoir to a high temperature reservoir, is called __________.

33. Coefficient of performance of refrigerator is __________.

34. Measure of disorder is called __________.

35. The change in entropy is __________.

36. Second law of th4ermodynamics can be restated in terms of entropy as __________.

Chapter 12

Electrostatics

1. Mathematically coulomb’s Law of electrostatic is stated as F = __________.

2. The value of Coulomb’s constant k is given as __________.

3. The value of coulomb’s constant k in terms of permitivity of free space is given as __________.

4. The value of permitivity of free space is __________.

5. The unit of charge in SI system is __________.

6. One coulomb is that quantity of charge which when placed one metre from an identical charge in vacuum (or air) repels with a force equal to __________.

7. Coulomb’s force in the medium of relative permitivity Îr is given as __________.

8. 1 mC = __________.

9. 1pC = __________.

10. The space around any charge in which its influence could be felt by another charge placed there is called __________.

11. Electric field intensity E at any point surrounding the charge q is defined as __________.

12. If E represents electric field intensity and qo a point charge, then mathematically electric field intensity is defined as __________.

13. The electric field intensity at a point in an electric field is defined as __________.

14. The potential at a point, a distance r from a charge q is __________.

15. 1 volt = __________.

16. The quantity DV/DR is called __________.

17. The unit of electric intensity E, N/C is equivalent to __________.

18. The amount of energy acquired or lost by an electron when it is displaced across two points between which the potential difference is one volt is called __________.

19. 1eV = __________.

20. A device, which is used to store electric charge, is called __________.

21. The ratio Q/V is called __________.

22. The unit of capacitance is __________.

23. 1 farad = __________.

24. 1 micro farad = __________.

25. 1 pico farad = __________.

Chapter 13

Current Electricity

1. If A is the area of cross-section of a conductor and L is the length of the conductor, then resistivity “r” of a conductor is given by the relation __________.

2. The unit of resistivity is __________.

3. Resistance ‘R’ of a wire of length ‘L’, cross-section area ‘A’ and resistivity ‘r’ is given by the relation __________.

4. If same current passes through all the resistance and the resistors provide a simple path to the flow of the current, then they are said to be connected in __________.

5. If two or more resistors are joined such a way that one end of each resistor is connected to one terminal of the battery while the other ends are connected to the second terminal of the battery, they they are said to be connected in __________.

6. If resistors R1, R2, R3 ….R4 are connected in series then the resultant equivalent resistance Re is given by __________.

7. If resistors R1, R2, R3 ….R4 are connected in parallel then the resultant equivalent resistance Re is given by __________.

8. Resultant resistance of the resistors joined in parallel is __________than the least resistance of the component resistors.

9. As the charge flows through the conductor energy is dissipitated in the form of __________.

10. Mathematically power dissipitated is defined as __________.

11. Power dissipated is also defined as __________.

12. Power dissipated is also defined as __________.

13. Power dissipated is also defined as __________.

14. The unit of power __________.

15. 1 watt = __________.

16. The practical unit of power in common use is __________.

17. The amount of energy delivered by the current in one hour when it supplies energy at the rate of 100 J/s is called __________.

18. 1 kwh = __________.

Chapter 14

Magnetism and Electromagnetism

1. The magnitude of the magnetic force F on the wire of length ‘l’ carrying current I is given by __________.

2. The force exerted on a wire of length one metre carrying one ampere current placed at right angle to the field is called __________.

3. Mathematically magnetic induction is defined as __________.

4. The S.I unit of magnetic induction is __________.

5. Gauss’s (G) is a unit of __________.

6. 1T(Tesla) = __________G.

7. Torque on a current carrying rectangular loop of area A and having N turns and placed in a magnetic field B is given by the relation __________.

8. The total number of lines of magnetic induction passing through a surface placed perpendicular to the magnetic field is called __________.

9. Mathematically magnetic flux is defined as __________.

10. Magnetic flux f, through certain area A is maximum if the angle between the magnetic field B and area A is __________.

11. Magnetic flux f, though certain area A is zero if the angle between the magnetic field B and area A is __________.

12. The SI unit of magnetic induction is __________.

13. Nm/A is commonly called __________.

14. 1 Wb/m2 is known as __________.

15. The magnetic field B is also called __________.

16. The force on a charged particle of charge ‘q’ moving with velocity ’v’ in a magnetic field of strength ‘B’ is given by __________.

17. An electron travelling with a velocity v describes a circular path when it enters a uniform magnetic field such that __________.

18. Ampere’s law is analogous to __________.

19. The dot product of B and I around any closed path equals to moI, where I is the total steady current threaded by the path. This is called __________.

20. Mathematically, Ampere’s law can be written as __________.

21. The value of permeability of free space mo is __________.

22. By winding wire in a helix around a cylindrical surface, we will get __________.

23. If there are n turns per unit length of the solenoid and each turn carries a current I, then the magnetic field B of a solenoid is given by __________.

24. A solenoid that has been bent into a circle is called __________.

25. The magnetic field of a toroid is given by __________.

26. The current produced by moving the loop by wire across a magnetic field is called __________.

27. The product of induced current and resistance of the wire i.e. I x r gives __________.

28. The generation of induced emf in a circuit is known as __________.

29. When the magnetic flux changes through a loop on a coil, an induced emf is produced in it. This is called __________.

30. An induced emf always drives a current whose magnetic field opposes the original change in flux. This is called __________.

31. Mathematically Faraday’s law of electromagnetic induction is defined by the relation __________.

32. “The direction of an induced current is such as to oppose the cause producing it.” This is called __________.

33. Mathematically mutual inductance is written as __________.

34. Mutual inductance is measured in __________.

35. Vs/A is known as __________.

36. If the current changing at the rate of one ampere per second in the primary causes an induced emf of one volt in the secondary, then the mutual inductance of the two coils is said to be __________.

37. In the relation emf = , L is called __________.

38. The emf linked with the same coil when the rate of change of current in the coil is unity, is called __________.

39. Non-inductive resistances are used in __________.

40. The induced emf generated as a result of the motion of the wire through the magnetic field is called __________.

41. If v is the velocity with which the wire is dragged, I is the length of the wire and B is the magnetic field, then motion emf is written as __________.

42. A device, which produces a voltage difference between two terminals by changing flux through the coil, is called __________.

43. The voltage delivered by an electric current generator at any instant is given by the equation __________.

44. The maximum voltage delivered by an electric current generator at any instant is given by the equation __________.

45. A device, which gives unidirectional and a practically constant current is called __________.

46. A device, which converts electrical energy into mechanical energy, is called __________.

47. A device, which converts AC voltage of one magnitude into another AC voltage of required magnitude, is called __________.

48. The condition for step-up transformer is __________.

49. The condition for step-down transformer is __________.

50. A device used for the detection and measurement of current is called a __________.

51. Whenever a conductor of length, say I, carrying current I is placed in a magnetic field of strength B, it experiences a force given by __________.

52. When a low resistance, called a shunt is connected in parallel with the galvanometer, it is converted into __________.

53. When a resistor of high resistance is connected in series with the galvanometer it is converted into __________.

54. The shunt resistance Rs of an ammeter is given by __________.

55. The high resistance Rh of voltmeter is given by __________.

56. An instrument, which can measure and compare potential without drawing any current from the circuit is known as __________.

57. An instrument, which is used to measure current, voltage and resistance is called __________.

Chapter 15

Atomic Spectra

1. Mathematically Balmer Series is represented as __________, where R is called Rydberg constant.

2. Mathematically Lyman Series is represented as __________, where R is called Rydberg constant.

3. Mathematically Paschen Series is represented as __________, where R is called Rydberg constant.

4. Mathematically Brackett Series is represented as __________, where R is called Rydberg constant.

5. Mathematically Pfund Series is represented as __________, where R is called Rydberg constant.

6. Lyman Series lies in __________.

7. Balmer Series lies in __________.

8. Paschen Series lies in __________.

9. Brackett Series lies in __________.

10. Pfund Series lies in __________.

11. According to Bohr’s theory of hydrogen atom the angular momentum of the electron about the nucleus is an integral multiple of __________.

12. According to Bohr’s thoery of hydrogen atom, the radii rn of stationary electron is given by the equation __________.

13. According to Bohr’s theory of hydrogen atom, the speed vn of an electron is given by the equation __________.

14. According to Bohr’s theory of the hydrogen atom, the radii rn of stationary electron orbits are related to the principle quantum number n as __________.

15. According to Bohr’s theory of hydrogen atom, the speed vn of the electron in a stationary orbit is related to the principle quantum number n as __________.

16. According to Bohr’s theory of the hydrogen atom, the total energy of the hydrogen atom with its electron revolving in the nth stationary orbit is given by the equation __________.

17. According to Bohr’s theory of the hydrogen atom, the total energy of the hydrogen atom with its electron revolving in the nth stationary orbit is given by the equation __________.

18. If the electrons in the hydrogen atom jumps from an orbit whose quantum number is n to an orbit whose quantum number is p, it emits a photon of wavelength l, given by __________.

19. The wavelength of x-rays is of order of __________.

20. In an x-ray tube, electrons are accelerated by applying a high voltage V. If e is the electronic charge and h the Plank’s constant, the highest frequency Vmax of the emitted x-rays is given by __________.

Chapter 16

The Nuclear Physics

1. The charge on electron is __________.

2. The mass of electron is __________.

3. The dimensions of the nucleus are of the order of __________.

4. The atomic region surrounding the nucleus is of the order of __________.

5. The number of neutrons N is equal to __________.

6. One gram mole of any substance contains __________ number of atomic nuclei.

7. Mass of the nucleus is of the order of __________.

8. Atomic mass is measured in __________.

9. 1 amu is equal to __________ of the mass of the carbon atom.

10. 1 amu is equal to __________.

11. The mass of electron on a unified atomic mass scale (amu) is equal to __________.

12. The mass of proton on a unified atomic mass scale (amu) is equal to __________.

13. The mass of nuetron on a unified atomic mass scale (amu) is equal to __________.

14. __________ is a alpha particle.

15. The velocity of brays is from __________.

16. __________ radiation are not emitted by a radioactive isotope.

17. The isotope of hydrogen, which is radioactive, is __________.

18. The energy released when one amu is wholly converted into energy is __________.

19. When an element emits b-particle, its atomic number Z changes by __________.

20. The g-decay process is mathematically written as __________.

21. A radioactive element X has atomic number Z and atomic mass number A. It decays by the emission of an alpha particle and a gamma ray. The new element is __________.

22. Mathematically half life T1/2 of an element is written as __________.

23. Theoritically the neutron induced fission of one kilogram of uranium nuclei into smaller nuclei releases energy approximately equal to __________.

24. The isotope of uranium, mostly used as fuel in a common nuclear reactor is __________.

25. In breeder reactor, __________ isotope of uranium is used as a fuel.

Chapter 17

Advent of Modern Physics

1. The Galilean transformation of the space-time coordinates of a point between the primed coordinates (x’, y’, t) and the unprimed coordinates (x, y, t) is given by __________.

2. If mo is the rest mass of an object in a frame of reference, then the mass m as measured by an observer moving with a velocity v relative to the object is __________.

3. If lo is the length of an object in a stationary frame of reference, then the length l of the same object as viewed by the observer in frame of reference moving with a velocity v relative to the object is given by __________.

4. If to is the time instant of time of an event as measured by an observer in a moving frame of reference, the time instant t as it appears to a stationary observer with respect to the moving one is given by __________.

5. Two photons are traveling in opposite directions with velocity c. The relative velocity of one with respect to the other is __________.

6. An observer measures the length of a space-ship and finds that it is exactly one-third of its proper length. __________ is the speed of the space-ship relative to the observer.

7. A rod has a proper (or rest) length Lo. the length of the same rod as measured by an observer moving with a velocity v relative to the rod, is given by __________.

8. The value of Plank’s constant is __________.

9. The velocity of photon is __________.

10. Photoelectric effect is governed by the equation __________.

11. Einstein’s photoelectric Equation is mathematically written as __________.

12. For most of the metals, the work function f is of the order of __________.

13. The photoelectric threshold for a certain metal surface is 330A°. __________ is the maximum kinetic energy of the photoelectron released, if any, by a radiation of wavelength 1100A.

14. A Photocell is based on __________.

15. The process of scattering of an X-ray photon by an electron is called __________.

16. Compton Effect is a phenomenon in which electromagnetic waves exhibit __________.

17. The Compton effect results in the shift in wavelength of the scattered photon and the incident photon by an amount __________.

18. Mathematically Uncertainty Principle is stated as __________.