Physics
Inter Part-II  
Gujranwala
Board 201 6
Paper: II
Time: 20 min.
OBJECTIVE
Marks: 17

Note: You have foLr choices for each objective type question as A, B, C and D. The   choice which you think is correct, fill that circle in front of that question number. Use marker or pen to fill the circles. Cutting or filling two or more circles will result in zero mark in that question. Attempt as many questions as given in objective type question paper and leave others blank.

• When a nucleus emits an alpha particle its atomic mass decreases by:

(A) 1
(B) 2
(C) 3
(D) 4

• Energy stores in an inductor is given by:

(A)1/2Ll
(B) 1/2L²l
(C) 1/2Ll²
(D) 1/2L²l²

• Wave nature of light appears in:

(A) pair production
(B) Compton effect
(C) photoelectric effect
(D) interference

• SI unit of current gain is:

(A) ampere
(B) volt
(C) coulomb
(D) no unit

• The Curie temperature for iron is:

(A) 750°C
(B) 650°C
(C) 550°C
(D) 850°C

• The SI unit of electric flux is:

(A) N mc^-2
(B) N m²c^-1
(C) N c m^-2
(D) N m ^c2

• Colour code of yellow color is:

(A) 2
(B) 3
(C) 4
(D) 5

• Two parallel wires carrying current in the same direction:

(A) attract each other
(B) repel each other
(C) cancel their fields
(D) no effect on each other

• The sum of positive and negative peak values is called:

(A) average value
(B) r m s value
(C) peak value
(D) P-P value

• One gray (Gy) is equal to:

(A) 1.6 x10^-19 J
(B) 1.6 x10^-10 J/ kg
(C) 1J / kg
(D) 4J / kg

• If the motor is overloaded then magnitude of back ernf:

(A) increases
(B) decreases
(C) zero
(D) remains constant

• Balmer series lies in:

(A) infrared region
(B) visible region
(C) ultraviolet region
(D) far ultraviolet region

• The platinum wire becomes white at a temperature of:

(A) 1600°C
(B) 1100°C
(C) 1000°C
(D) 600°C

• For rectification we use:

(A) transformer
(B) diode
(C) choke
(D) generator

• The phase angle at +ve (positive) peak is:

(A) π/2
(B) π
(C) 3π/2
(D) 2π

• The brightness of spot in CRO is controlled by:

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

• The value of ϵ₀ permittivity for free space is :

(A) 8.85 x10^-12c²N^-1m^-2
(B) 8.85 x 10^-12Nm²C^-2
(C) 8.85 x10^-12Nm C^-2
(D) 8.85 x10 ^-12m2N ^-2c²

Physics
Inter Part-II Gujranwala
Board 2016
Paper II
Time: 3:10 Hours
SUBJECTIVE
Marks: 83

Note: Section I is compulsory. Attempt any three (3) questions from Section II and any three (3) parts from Section III

(SECTION - I)

2. Write short answers to any EIGHT questions: (2x8=16)

• What is the orientation of the surface in an electric field to get maximum flux through it?
• Suppose that you follow an electric field line due to a positive point charge. Do electric field and the potential increase or decrease?
•  Do the electric lines of force cross each other? Explain.
• Prove that unit of series RC circuit is second.
•  What is the function of grid in cathode ray oscilloscope?
• How can you use a magnetic field to separate isotopes of chemical element?
•  Why the resistance of an ammeter should be very low?
• What is the effect on magnetic field inside a solenoid if the length of solenoid is doubled and no. of turns remains the same?
•  Four unmarked wires emerge from a transformer. What steps would you take to determine the turn ratio?
• Can a step-up transformer increase the power level? Explain.
• If area of the loop and magnetic field both are changing and still have no induced emf. Explain why?
• What is meant by commutator in D.C. generator?

3.Write short answers to any EIGHT questions: (2x8=16)

• Do bends in a wire effect its electrical resistance? Explain.
• Is the filament resistance lower or higher in a 500 W, 220 V light bulb than in 100 W, 220 V bulb?
• Give two substances having negative temperature co-efficient.
• A sinusoidal current has rms value of 10 A. What is the maximum or peak value?
• Explain how the reception of a particular radio station is selected on your radio set?
• How does doubling the frequency effect the reactance of (a) an inductor (b) a capacitor?
• What are ferromagnetic substances? Give an example.
• Define stress and strain. What are their SI units?
• How n-type semi-conductors are formed.
• How does the motion of an electron in an n-type substance differ from the otion of holes in a p-type substance?
• Why is the base current in a transistor very small?
• Why charge carriers are not present in the depletion region?

4.Write short answers to any SIX questions: (2x6=12)

• Which have lower energy quanta? Radio waves or x-rays.
• When light shines on a surface. Is momentum transferred to the metal surface?
• As a solid is heated and begins to glow. Why does it first appear red?
• Can x-rays be reflected, refracted, diffracted and polarized just like any other waves? Explain.
• Write down the two uses of LASER.
• Why are heavy nuclei unstable?
• What is the function of moderators in a nuclear reactor?
• If someone accidentally swallows in an a-source and a n-source which would be more dangerous to him? Explain why?
• What is meant by the term "critical mass"?

(SECTION - II)

5. (a)Define electric flux and give its units, also show that the electric flu through a closed surface depends upon the medium and the electric charge enclosed by the closed surface. (5)

(b)The resistance of an iron wire at 0°C is 1 x 10⁴ Ω What is the resistance at 500°C if the temperature co-efficient of resistance of iron is 5.2 x 10^-3K^-1 ? (3)

6. (a)State and explain Ampere's law. Apply it to calculate the magnetic field due to current through a soleniod. 5

(b)A solenoid coil 10.0 cm long has 40 turns per cm. When the switch is closed, the current rises from zero to its maximum value 5.0 A in 0.01s. Find the energy stored in the magnetic field if the area of cross section of the soleniod is 28 cm².

7. (a)Explain the behaviour of A.C. through an inductor. Also show that the reactance of a coil depends upon the frequency of the A.C. and inductance I. (5)

(b) A 1.25 cm diameter cylinder is subjected to a load of 2500 kg. Calculate the stress on the bar in mega Pascals. (3)

8. (a)Define rectification. What are its types? Discuss half- wave rectification. (5)

(b)What is the de-Broglie wavelength of an electron whose kinetic energy is 120 eV. (3)

9. (a) According to Bohr's theory, find the radi of different stationary orbits of an electron in hydrogen atom and also find Quantized Energies? (5)

(b) Find the mass defect and binding energy for Tritium, if the atomic mass of Tritium is 3.016049 u. (3)

(Section III Practical)

10.(a) Give answers to any FOUR questions: (2x4=8)

• Define resistance and its unit.
• What is meant by half deflection method? Explain briefly.
• What is rheostat? Describe its principle.
• What is meant by internal resistance of a cell? Explain briefly.
• What is meant by Ohmic and non-Ohmic conductors?
• What is meant by break down voltage? Explain briefly.
• What is meant by threshold frequency? Also define work function.
• What do you mean by donor impurity and accepter impurity?

(b) Write down the brief procedure to find the resistance of a galvanometer by half deflection method. (3)

OR

Write down brief procedure to study the relation between the current passing through a tungsten filament lamp and the potential applied across it.

(c) Answer the questions given below on the basis of the following graph-A:

Find the slope of V-ℓ.) Graph-A.

What do you infer from the V-ℓ graph-A.

OR

Answer the questions given below on the basis of the following graph-B:

• Find the slope of the graph-B.
• What do you infer from the graph-B?