Physics
Lahore Board 2015
Inter Part-lI
Group – I
Time: 20 Min.
Objective Type
Marks = 17
Note: Four possible answers A, B, C and D to each question are given. The choice which you think is correct, fill that circle in front of that question with marker or pen ink in the answer-book cutting or filling two or more circles will result in zero mark in that question.

• The value of coulomb’s constant (K) in SI units is:

(A) 9x10⁹Nm²C^-2
(B) 9x10⁹NC²m^-2
(C) 9x10⁹N^-2 m²C²
(D) 9x10⁹Nm²C²

• Which one of the following can be taken as measure of electric field intensity:

(A)
(B)
(C)
(D)

• Specific resistance of a material depends upon:

(A) Length
(B) Area
(C) Temperature
(D) Both A&B

• 1 tesla is equal to:

(A) 1 NmA^-1
(B) 1 Nm^-1A^-1
(C) 1 Nm^-1
(D) 1 Nm^-2A^-1

• The brightness of the spot on CRO screen is controlled by:

(A) Anode
(B) Cathode
(C) Grid
(D) Deflecting plates

• The winding of the electromagnet in motor are usually called:

(A) Magnetic coils
(B) Field coils
(C) Electric coils
(D) Electric-o-electric coils

• The mutual induction plays role in:

(A) Generator
(B) Galvanometer
(C) Transformer
(D) D.C. motor

• The velocity of an oscillating charge as it moves to and fro along a wire is:

(A) Changing
(B) Constant
(C) Infinite
(D) Zero

• Choke consumes extremely small:

(A) Current
(B) Charge
(C) Power
(D) Potential

• Which one pair belongs to accepter impurity?

(A) Arsenic, phosphorus
(B) Boron, gallium
(C) Antimony, indium
(D) Arsenic, antimony

• Potential difference across two terminal of silicon diode at 300 k is :

(A) 0.3 V
(B) 0.7 V
(C) 0.9 V
(D) 1.2 V

• The thickness of base in a transistor is of the order of:

(A) 10^-3m
(B) 10^-9m
(C) 10^-6m
(D) 10^-6mm

• Potassium cathode in photocell emit electrons for a light:

(A) Visible
(B) Infra-red
(C) Ultra violet
(D) X-rays

• The rest mass energy of an electron positron pair is:

(A) 0.51 Mev
(B) 1.02 Mev
(C) 1.2 Mev
(D) 1.00 Mev

• Production of X-rays is reverse process of:

(A) Photo-electric effect
(B) Compton effect
(C) Annihilation
(D) Pair production

• Two down and one up quarks make:

(A) Proton
(B) Neutron
(C) Photon
(D) Positron

• Which paricle has larger rang in air:

(A) ᵅ-particle
(B) ᵧ-particle
(C) ᵦ-particle
(D) Neutron

Physics
Lahore Board 2015
Inter Part-lI
Group – I
Time: 3.10 hrs.
Essay Type
Marks = 83

SECTION -I

2. Write short answers to any EIGHT (8) questions: (16)

• State gauss’s law
  
• Define electron-volt prove 1ev = 1.6 x 10^-19 j
• Electric line of force never cross. Why
• Why dose the picture of T.V screen become distort when a magnet is brought near the screen?
• Why the voltmeter should have a very high resistance?
• What is meant by Lorentz force?
• How can you use a magnetic field to separate isotopes of chemical element?
• Do electrons tend to go to region of high potential or of low potential?
• State lenz’s law
• Show that ε and have the same units
• Does the induced emf always act to decrease the magnetic flux in circuit
• Cana step-up transformer increase the level?

3. Write short answers to any EIGHT (8) questions: (16)

• Define Kirchhoff’s of circuit analysis
• Do bends in a wire affect its electrical resistance? Explain
• What is wheatstone bridge? Sketch its circuit diagram
• What is the main reason for the world wide use of A.C.?
• How does doubling the frequency affect the reactance of a capacitor?
• What do you mean by amplitude modulation?
• Define modulus of elasticity and write its unit.
• What is meant by strain energy? Give its relation
• Distinguish between crystalline and amorphous solids.
• Write four uses of photo diode.
• Write two characteristics of op. amplifier
• Why is the base crrent in a transistor very small?

4. Write short answers to any SIX (6) questions: (12)

• If the speed of light were infinite what would the equations of special theory of relativity reduce to?
• Which photon red green or blue carries the most
• Energy (b) Momentum?
• State uncertainty principle give its two mathematical forms
• Explain why laser action could not occur without population inversion between atomic levels?
• Give two postulates of Bohr’s model of hydrogen atom.
• Describe a brief account of interaction of various types of radiations with matter
• State the advantages and disadvantages of nuclear power
• Why are heavy nuclei unstable?
• What are hadrons and leptons? Explain with Examples:

SECTION-II

Note: Attempt any THREE questions.

5. (a) What is potentiometer? How it can be used as: (5)

   (i) Potential divider
   (ii) Measuring of emf of a cell?

   (b) The electronic flash attachment for a camera contains a capacitor for storing the energy used to produce the flash. In one such unit, the potential difference between the plates of a 750 uF capacitor is 330V Determine the energy that is used to produce the flash. (3)

6. (a) Derive an expression for the force on a charge particle moving in the magnetic field. (5)

(b) Two coils are placed side by side. An emf of 0.8 V is observed in one soil when the current is changing at the rate of 200 ^AS-1 in the other coil. What is the mutual inductance of the coil? (3)

7. (a) Define extrinsic and intrinsic semi conductors. How can we obtain P-type and N-type substabces? (5)

(b) A 100 uF capacitor is connected to an alternating voltage of 24V and frequency 50 Hz. Calculate: (3)

(i) Reactance of a capacitor
(ii) Current in the circuit

1. (a) What is operational amplifier? Derive relation for the gain of non-inverting op.amplifier. (5)

(b) An electron is placed in a box about the size of an atom that is about 1.0 X 10^-10m. What is the velocity of the electron? (3)

9. (a) Explain inner shell transitions and X-rays production. (5)

(b) If ²³³ ₉₂ U decays twice by a-Emission, what is the resulting isotope? (3)

SECTION – III (Practical Part)

A . Attempt any four questions. (8)

• How will you check whether the connection of slide wire bridge are correct?
• Write down the equations to find the values of R_s and R_H
• In half deflection method value of R = 5400 Ω and S = 120 Ω. Find the resistance of galvanometer.
• Draw the circuit diagram of half deflection method.
• What do you mean by forward and reverse bias?
• State ohm’s law and give two examples of non-ohmic devices.
• Draw the symbol and truth table of and gate.
• What is neon flash lamp?

B . Write down brief procedure to determine the resistance of galvanometer by half deflection method.

OR

Write down the brief procedure to study the variation of photo- electric current with intensity of light using a photocell.

C . Answer the questions given below on the basis of following graph:

• Find the slope of the graph.
• What do you inter from the graph?

Image page no. 119

OR

• Find the slope of the graph.
• What do you inter from the graph?

Image page no. 119

Physics
Lahore Board 2015
Inter Part-lI
Group – II
Time: 20 Min.
Objective Type
Marks = 17
Note: Four possible answers A, B, C and D to each question are given. The choice which you think is correct, fill that circle in front of that question with marker or pen ink in the answer-book cutting or filling two or more circles will result in zero mark in that question.

• The concept of an electric field line is introduced by:

(A) Coulomb
(B) Fraday
(C) Einstein
(D) Joseph Henry

• Two opposite point charge of same magnitude separated by distance 2d, electric potential mid-way between them is:

(A) 1 V
(B) 2 V
(C) Zero
(D) V/2

• If the resistance of 500 Ω has fourth band of silver colour then its upper maximum resistance will:

(A) 600 Ω
(B) 550 Ω
(C) 450 Ω
(D) 400 Ω

• The S.I unit of magnetic flux is given by:

(A) NmA^-1
(B) NA^-1m^-1
(C) Nm²A^-1
(D) Nm^-1A

• If the number of turns become double but length remain same, then magnetic field in the solenoid become:

(A) Half
(B) Double
(C) Remain same
(D) Zero

• Commentator was invented in:

(A) 1736
(B) 1834
(C) 1935
(D) 1885

• The working principle of transformer is :

(A) Self induction
(B) Fraday’s law
(C) Mutual induction
(D) Electromagnetic induction

• The frequency of A.C source used in Pakistan is:

(A) 50 Hz
(B) 60 Hz
(C) 45 Hz
(D) 70 Hz

• In a pure inductive A.C. circuit the current:

(A) Lags behind voltage by 90°
(B) Leads the voltage by 90°
(C) In phase with voltage
(D) Leads the voltage by 270°

• Which one of the following is crystalline solid:

(A) Zirconia
(B) Glassy soil
(C) Natural rubber
(D) Polystrene

• Light emitting diodes (LED) are made from semi-conductors:

(A) Silicon
(B) Germanium
(C) Carbon
(D) Gallium arsenide

• The open loop gain of the amplifier is order of:

(A) 10²
(B) 10⁶
(C) 10⁵
(D) 10¹²

• The value of Wien’s constant is:

(A) 2.9 x 10^-3mK
(B) 2.9 x 10³mK
(C) Power
(D) 5.67 x 10^-8wm^-2K^-4

• Einstein was awarded Nobel Prize in physics in:

(A) 1905
(B) 1911
(C) 1918
(D) 1921

• In Hulium-Neon laser, discharge tube is filled with neon gas:

(A) 10%
(B) 15%
(C) 85%
(D) 90%

• The number of isotopes of cesium are:

(A) 4
(B) 32
(C) 36
(D) 22

• Binding energy for deuteron nucleus is given by:

(A) 2.8 Mev
(B) 2.23 Mev
(C) 2.28 Mev
(D) 2.25 Mev

Physics
Lahore Board 2015
Inter Part-lI
Group – II
Time: 3.10 Hrs.
Eassy Type
Marks = 83

SECTION -I

2. Write short answers to any EIGHT (8) questions: (16)

• Describe the force or forces on a positive point charge when placed between parallel plates:
• With similar and equal charges
• With opposite and equal charges.
• If a point charge q of mass m is released in a non-uniform electric field with lines pointing in the same direction, will it make a rectilinear motion?
• Define dielectric constant. Give its mathematical form
• Define unit of capacitance. Give its units.
• Why the resistance of an ammeter should be very low?
• How can you use a magnetic field to separate isotopes of chemical element?
• Two charged particles are projected into a region where there is a magnetic field perpendicular to their velocity if the charges are deflected in opposite directions what can you say about them?
• Define current sensitivity of a galvanometer
• In a certain region the earth’s magnetic field point vertically down when a plane flies due north which wing is positively charged?
• Can a D.C motor be turned into a D.C generator? What changes are required to be done?
• When an electric motor such as an electric drill is being used does it also act as a generator? If so what is the consequence of this ?
• What is motional emf? Give its formula

3. Write short answers to any EIGHT (8) questions: (16)

• Define conventional current and electronic current.
• What are the difficulties in testing whether the filament of a lighted bulb obeys Ohm’s law?
• What is Wheatstone bridge? How can it be used to determine the unknown resistance?
• Define choke
• A circuit contains an iron cored inductor a switch and a D.C source arranged in series the switch is closed and after an interval re-opened. Explain why a spark jumps across the switch contacts.
• Explain the conditions under which electromagnetic waves are produced from a source.
• Define elasticity and plasticity.
• Define critical temperature and curie temperature
• What is meant by hystresisloss? How it is used in the construction of a transformer?
• What is the effect of forward biasing and reverse biasing on the width of depletion region?
• Why photodiode is operated in reverse biased state?
• Write down the truth table of exclusive OR gate.

4. Write short answers to any SIX (6) questions: (12)

• Which has the lower energy quanta? Radio waves or X-rays.
• Why do not we observe a Compton effect with visible light?
• If an electron and a proton have the same de-Broglie wavelength which particle has greater speed?
• Is energy conserved when an atom emits a photon of light?
• What are the advantages of laser over ordinary light?
• Is a nucleus has half life of one year does this mean that it will completely decay after two years?
• A particle which produces more ionization is less penetrating why?
• State the advantages and disadvantages of fusion power from the point of view of safty pollution and resources
• Define half life of an element with example.

SECTION-II

Note: Attempt any THREE questions.

5. (a) Define absolute potential and derive expression for the electrical potential at a certain point due to a point due a point charge (5)

(b) How many electrons pass through an electric bulb in one minute if 300 mA current is passing through it? (3)

6. (a) State Ampere’s law and derive the relation B = μ₀ nl for solenoid. (5)

(b) A square coil of side 16 cm has 200 turns and rotates in a uniform magnetic field of magnitude 0.05 T. If the peak emf is 12V, what is angular velocity of the coil? (3)

7. (a) Explain R-L-C series resonance circuit and give its properties. (5)

(b) A 1.0 m long copper wire is subjected to stretching force and its length increases by 20 m calculate the tensile strain and the percent elongation which the wire undergoes. (3)

8. (a) Explain photoelectric effect on the basis of Einstein’s quantum theory also derive Einstein equation (5)

(b) Calculate the gain of an amplifier in which the collector resistance RC is 5k Ω. The input resistance between the base and emitter of a typical transistor is 2.5 k Ω and value of its ᵦ = 100. (3)

9. (a) How isotopes are detected with a mass spectrograph? (5)

(b) Compute the shortest wavelength radiation in the blamer series what value of n must be used? (3)

SECTION – III (Practical Part)

A . Attempt any four questions. (8)

• What is shunt?
• Draw a circuit diagram for resistance of a galvanometer by half deflection method
• What should be the characteristics of a good voltmeter?
• What is thermostat?
• What is meant by photoelectrons?
• Draw a table for studying the variation of electric current with intensity of light using a photocell.
• Write down the symbol and truth table of and gate.
• What is meant by striking voltage?

B . write down the procedure for finding the resistance of galvanometer by half deflection method 3

OR

Write down the procedure for studying the relation between current and capacitance when different capacitors are used in A.C circuit

C . Answer the question given below on the basis of following graph

• Find the slope of the graph.
• What do you inter from the graph?

Image page no. 125

OR

• Find the slope of the graph.
• What do you inter from the graph?