Sahiwal Board 2015
Physics
Inter (Part-II)
(Objective Type)
Time Allowed: 20 Minutes 
Max. Marks: 17

Note: You have four 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.

Question #1
Circle the correct option i.e. A/B/C/D. Each part carries one mark.

• Absorbed Dose "D" is defined as:

(a) M/E
(b) E/C
(c) C/m
(d) E/M

• The dead time of G.M tube is:

(a) 10^-3 sec
(b) 10^-6 sec
(c) 10^-4sec
(d) 10^-8 sec

• If electrons jumps from second orbit to first orbit in hydrogen atom it emits photon of:

(a) 3.40 ev
(b) 10.20 ev
(c) 13.6 ev
(d) 3.8 ev

• Antiparticle of electron is:

(a) Proton
(b) Photon
(c) Neutron
(d) Positron

• The rest mass of photon is:

(a) infinite
(b) zero
(c) 1.6 x10^-27 kg
(d) 3 x 10⁸ kg

• The width of central region of a transistor is:

(a) 10^-4m
(b) 10^-6m
(c) 10^-3m
(d) 10^-9m

• The use of LDR is in the circuit of:

(a) Night switch
(b) Logic gate
(c) Rectifier
(d) Oscillator

• The critical temperature of mercury is:

(a) 1.18 K
(b) 4.2 K
(c) 3.72 K
(d) 7 2 K

• The most common source of A.0 is:

(a) Motor
(b) Battery
(c) Generator
(d) Solar cell

• Power dissipated in pure conductor is:

(a) Large
(b) Small
(c) Infinite
(d) Zero

• Transformer is used to change:

(a) Electric power
(b) Magnetic power
(c) Alternating voltage
(d) Phase of A.0

• When a motor is over loaded, then the magnetic of back emf:

(a) Increase
(b) Decrease
(c) Remain constant
(d) Zero

• Two parallel straight wires carrying current in same direction will:

(a) Repel each other
(b) Attract each other
(c) No effect
(d) May repel or attract

• When a charge is projected perpendicular to a uniform magnetic field, its path is:

(a) Spiral
(b) Helix
(c) Ellips
(d) Circular

• The SI unit of resistivity is:

(a) Ω m^-2
(b) Ω m^-1
(c) Ω m
(d) Ω

• The number of electrons in one coulomb charge is equal to:

(a) 1.6 x 10^-19
(b) 6.25 x 10^-19
(c) 6.25 x 10¹⁸
(d) 6.25 x 10¹⁹

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

(a) Changing
(b) Constant
(c) Infinite
(d) Zero

Sahiwal Board 2015
Physics
Inter (Part-II)
(Subjective)
Time Allowed: 2.10 Hours
Max. Marks: 83
Section-I

2. Write short answers to any eight parts. (8x 2 =16)

1. Define electrostatics and electric force.
2. Do electrons tend to go to region of high potential or of lowq potential?
3. Elelctric lines of force never cross one another. Why?
4. Convert 1 Joule into electron volt.
5. Define galvanometer and cathode ray oscilloscope.
6. Why does the picture on a T.V screen become distorted when a magnet is brought near the screen?
7. Name the main parts of C.R.O.
8. What is the Lorentz force?
9. Define induced emf and induced current.
10. Name the factors upon which the self inductance depends.
11. Show that Ԑ and have the same units.
12. What are the differences between motor and generator?

3. Write short answers to any eight parts, (8x 2 =16)

1. Do bend in a wire effects its electrical resistance? Explain.
2. Is the filament resistance lower or higher in a 500 W, 220 V light bulb than in a 100 W, 220 V light bulb?
3. Describe a circuit which will give a continuously varying potential.
4. How mant times per second will an incandescent lamp reach maximum brilliance when connected to a 50 Hz source?
5. How does doubling frequency affect reactance of (a) An inductor (b) capacitor?
6. What is meant by A.M and F.M?
7. Define (a) Paramagnetic substance (b) Diamagnetic substance
8. Define (a) Super conductor (b) Critical temperature
9. Define (a) Conduction band (b) Valence band
10. The anode of a diode is 0.2V positive with respect to its cathode. Is it forward biased?
11. Why is the base current in a transistor very small?
12. Why a photo diode is operated in reverse biased state?

4. Write short answers to any six parts. (6x 2=12)

1. Give postulates of special theory of relativity.
2. As a solid is heated and begans to glow. Why does it first appear red?
3. Why don't we observe a Compton effect with visible light?
4. Is energy conserved when an atom emits a photon of light?
5. What are the advantages of laser over ordinary light?
6. What is fluorescence?
7. What are isotopes? What do they have in common and what are their differences?
8. What do we mean by the term critical mass?
9. A particle which produces more ionization is less penetrating. Why?

SECTION-II

Note: Attempt any three (3) questions. (3x8= 24 )

Question #5
(a) Derive the relation for capacitance of a parallel plate capacitor and hence define electric coefficient.
(b) The potential difference between terminals of a battery in open circuit is 2.2 V. When it is connected across a resistance of 5Ω. The potential flls to 1.8V. Calculate the current and internal resistance of battery.

Question #6
(a) What is alternating current generator? Explain principle. Construction and theory of A.0 generator.
(b) How fast must a proton move in a magnetic field of 2.50 x 10^-3 T such that magnetic force is equal to its weight?

Question #7
(a) Define impedance. Derive expression for impedence and phase angle in RC series circuit excited by A.0 voltage.
(b) What stress would cause a wire to increase in length by 0.01% if the young's modulus of the wire is 10 x 10¹⁰ pa.

Question #8
(a) What is the digital system. Explain OR and AND gates with diagrams and truth tables.
(b) What is the mass of a 70kg man in a space rocket travelling at 0.8 C from us as measured from earth?

Question #9
(a) Write down postulates of Bohr's atomic model. Also write de-Broglic's interperation of bohr's orbit.
(b) The half life of an element is 9.70 hours. Find its decay constant.

SECTION-III
(PRACTICAL PART)

Question #10
(a) Give answers any four parts. (4x2 =8)

1. Name factors on which resistance of a conductor depends.
2. What is the difference between resistance and resistivity?
3. What is volt meter?
4. State Ohm's law.
5. What is PN junction?
6. What is photoelectric effect?
7. Give Boolean formula and truth table for AND gate.
8. In finding the internal resistance of a cell, why the deflection in galvanometer is zero at balance point.

(b) Write down bride produce to find resistance of voltmeter by drawing graph between R and 1/V.
Or
Write down brief produce to find internal resistance of a cell using potentiometer
(c) Answer the question on the basis of graph A or graph B.