Multan Board 2017
Physics PART - II
Time: 30 Minutes
Group-I
Note: Write answers to the questions on the objective answer sheet provided. Four possible answers A, B, C and D to each question are given. Which answer you consider correct, fill the corresponding circle  A, B, C and D given in front of each question with Marker or pen ink on the answer sheet provided.

SUBJECTIVE PART
SECTION B

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

1. Give similarity and difference between the Coulomb's and Gravitational Forces.
2. What is 'Photoconductor?
3. Why does Capacitance of a Capacitor increase when some dielectric material is inserted ' between the plates?
4. How can you identify that which plate of a charged capacitor is negatively charged?
5. How can you use a magnetic field to separate isotopes of chemical element'?
6. At a given instant, a proton moves in the positive X-direction in a region where there is magnetic field in the negative Z-direction. What ii the direction of the Magnetic 'Force?
7. What is Dead Beat Galvanometer?
8. Write the formula used to convert a Galvanometer into Voltmeter
9. Why the resistance of Voltmeter should high?
10. A light metallic ring is released from above into a vertical bar magnet with N - pole upside. Does the current flow clockwise or anticlockwise in the ring'
11. A suspended magnet is oscillating freely. in a horizontal plane. The oscillations are strongly damped when a metal plate is placed under the magnet. Explain why this occurs'?
12. What are the main causes of power loss in a transformer?

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

1. What is the difference between Conventional Current and Electronic Current?
2. What is Wheatstone Bridge? Write its Principle.
3. A potential difference is applied across the ends of a Copper wire. What is the effect on the drift velocity of free electrons by increasing the potential difference and decreasing the temperature of the wire?
4. What is frequency Modulation?
5. How does doubling the frequency affect the reactance of an inductor and a capacitor?
6. F.M. radio Waves provide a higher quality transmission of sound then A.M radio waves
7. Discus briefly.
8. Define Valence Band and Conduction Band.
9. Define Semiconductors in terms of Energy Bands.
10. Define Hysteresis Loop.
11. Define Rectification and write names of its types.
12. Why Ordinary Silicon Diodes do hot Mil light?

Q 4. Write short answer to any SIX (6) question

1. When ultraviolet light falls on certain dyes. Visible light is emitted. Why this happen when infrared light falls on these dyes?
2. Why don't we observe a Compton's effect with visible light?
3. If an electron and a proton have the same de Broglie wavelength, which particle has greater speed?
4. What are the advantages of lasers over ordinary light?
5. What is CAT - Scanner?
6. What is a radioactive tracer? Describe one application in medicine.
7. Which radiation dose would deposit more energy to the body?
8. 10 mGy dose to the hand or
9. 1 mGy does to the entire body
10. For what purpose Alcohol or Bromine is mixed with principal gas in Geiger tube?
11. Is it possible that fusion of two small nuclei may occur without collision of extremely high energy?
12. When ultraviolet light falls on certain dyes, visible light is emitted. Why does this not happen when infrared light falls on these dyes?
13. Why don't we observe a Compton's effect with visible light?
14. If an electron and a proton have the same de Broglie wavelength, which particle has greater speed?

Note: Attempt any THREE questions.

Q 5.

1. State Gauss's Law. How can you apply the Gauss's Law to calculate Electric Intensity due to an infinite sheet of charge?
2. 1.0 x 107 electrons pass through a conductor in 1.0u s. Find the current M ampere flowing through the conductor. Electronic charge is 1.6 x 10-19C.

Q 6.

1. Calculate torque on a current carrying coil placed in a uniform magnetic field.
2. A permanent magnetic D.C motor is run by a battery of 24 V. The coil of the motor has a resistance of 2Ω . It develops a back emf of 22.5 V when driving the load at normal speed. What is the current when motor just starts up? Also find the current when motor is running at normal speed.

Q 7.

1. Define phase of A.C. Also discuss the behaviour of R - C and R - L series circuits for the A.C.
2. The current flowing into the base of a transistor is 100uA. Find its collector current Ic its emitter current IE and the ratio = I_C/I_E if the value of current gain β is 100.

Q 8.

1. What is Compton Effect? Calculate Compton Wavelength.
2. A 1.0 meter long 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.

Q 9.

1. What is Solid State Detector? Describe its principle, construction and working.
2. Calculate the longest wavelength of radiation for the Paschen Series.

Multan Board 2017
Physics
PART - II
Time: 30 Minutes
Group 2
Note: Write answers to the questions on the objective answer sheet provided. Four possible answers A, B, C and D to each question are given. Which answer you consider correct, fill the corresponding circle  A, B, C and D given in front of each question with Marker or pen ink on the answer sheet provided.

• Two parallel straight wires carrying current in opposite direction:-

1. Repel each other
2. They cancel out their individual magnetic effect
3. Attract each other
4. Have no effect upon each other

• ______is not present in A.C generator.

1. Armature
2. Magnet
3. Slip-rings
4. Commentator

• _____expressions for mutual inductance is correct.

1. M =
2. M =
3. M =
4. M =

• The output voltage of an A.C generator at time t = T/4 is given by:

1. V = —Vo
2. V = Vo
3. V=0
4. V = V0/4

• The expression P = VI holds only when current and voltage are:-

1. In phase
2. Out of phase
3. At right angle to each other
4. At angle of 1200

• The substance in which atom cooperate with each other in such a way so as to exhibit a strong magnetic field is called:-

1. Ferromagnetic
2. Paramagnetic
3. Diamagnetic
4. Non-magnetic

• Logic gates can control some physical parameters like:-

1. Temperature, Pressure
2. Resistance, Inductance
3. Capacitance, Impedance
4. Current, Voltage

• The term invertor is used for:-

1. NOR gam
2. NAND gate
3. XNOR gate
4. NOT gate

• The velocity at which relativistic length of a body reduces to half of its original length is:-

1. 1/2 C
2. 3/2 C
3. 1/√2 C
4. √3/2 C

• When the K.E max of photoelectron is zero, the frequency of incident photon is_____ that of threshold frequency:-

1. Less than
2. Greater than
3. Much greater
4. Equal to

• The radiations emitted from hydrogen filled ifs mg tube can be analyzed into:-

1. Band Spectrum
2. Line Spectrum
3. Continuous Spectrum
4. Absorption Spectrum

• In Beta - deco,______ reaction takes place.

• The particles equal or greater in mass than that of protons is called:-

1. Bearyons
2. Leptons
3. Mesons
4. Quarks

• The drum in a photocopier is coated with a layer of:-

1. Aluminum
2. Silver
3. Gold
4. Selenium

• If a charged body is moved against the electric field it will gain:-

1. Elastic Potential Energy
2. Kinetic Energy
3. Gravitational Energy
4. Electric Potential Energy

• For Ohmic device the graph between V and I is,

1. A straight line
2. Curve
3. Hyperbola
4. Parabola

• A device used for detection of current is called:-

1. Inductor
2. Voltmeter
3. Capacitor
4. Galvanometer

SUBJECTIVE PART
SECTION B

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

1. Define Capacitance. Also define its unit.
2. Write down any two properties of Electric Field Lines.
3. Describe the force or forces on u positive point charge when placed between parallel plates
4. With similar and equal charge
5. With opposite and equal charges
6. Show that 1 eV = 1.6 x 10-19J
7. Define right hand rule for determining the direction of the magnetic field.
8. Define AVO meter and Ohmmeter.
9. Why does the picture on T.V screen become distorted when a magnet is brought near the screen?
10. Why the resistance of an ammeter should be very low?
11. Write down two methods to improve the efficiency of a transformer.
12. Show that ε and ΔΦ/Δt have the same units.
13. Can an electric motor be used to drive an electric generator with the output from generator being used to operate the motor?
14. When an electric motor, such as an electric drill, is being used, does it also act as a generator?

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

1. What is Wheatstone bridge? Draw its circuit diagram.
2. Why does the resistance of a conductor rise with temperature?
3. What is meant by the tolerance? Find the resistance of the resistor with colours Red - Violet - Orange - Silver.
4. What is Choke Coil?
5. What is meant by A.M and F.M?
6. How does doubling the frequency affect the reactance of (a) an inductor (b) a capacitor?
7. Distinguish between Crystalline and Polymeric Solids.
8. What is meant by Para and Ferromagnetic substances? Give examples for each.
9. Define Modulus of elasticity. Show that the units of Modulus of elasticity and stress are the same.
10. The inputs of a gate are I and 0. Identify the gate if its output is (a) 0 (b) J.
11. How does the motion of an electron in an - type substance differ from the motion of holes in a p - type substance?
12. Why a photo diode is operated in reverse biased state?

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

1. What is NAVSTAR navigation system?
2. What are the measurement on w bleb two observers in a relative motion will always agree upon?
3. What are the advantages of electron microscope over an optical microscope?
4. Define Ionization Energy and Ionization Potential.
5. What are the reasons of unstability of heavy nuclei?
6. Hydrogen atom contains one electron but its spectrum contains so many lines, explain
7. Define mass deficit and binding energy.
8. What are Background Radiations? Write the name of its two sources.
9. What do we mean by the term Critical Mass?
10. What is NAVSTAR navigation system?
11. What arc the measurements on which two observers in a relative motion will always agree upon'?
12. What are the advantages of electron microscope over an optical microscope?

SECTION C

Note: Attempt any THREE questions.

Q 5.

1. Define Absolute Electric Potential. Derive its relation due to a point charge.
2. A Platinum wire has resistance of 10 Ω at 0°C and 20 Ω at 273° C. Find value of temperature coefficient of resistance of Platinum.

Q 6.

1. Derive an expression for the energy stored in an inductor.
2. What current should pass through a solenoid that is 0.5 m long with 10.000 turns of Copper wire so that it will have a magnetic field of 0.4 T?

Q 7.

1. What is RLC - parallel circuit? Find the value of the resonance frequency and also write its four properties.
2. The current flowing into the base of a transistor is 100 μA. Find its emitter current IE. irthe value of current gain β is 100.

Q 8.

1. What is Doping? Explain formation of n - type and p - type semiconductors.