Bahawalpur board 2017
PHYSICS
Inter Part-2
Time Allowed: 3 Hours
Group 1
Note:-Three are THREE sections in this paper i.e. Section A. B and C. Attempt Section-A on the same paper and return it to the superintendent within the given time. No marks will be awarded for Cutting, Erasing or Overwriting. Marks of Identification will lead to UFM case, Mobile Phone etc. are not allowed in the examination hall.

Q1. Write the correct option i.e. A, B, C or D in the empty, box provided opposite to each part.

• The S.I. Unit of Electron Flux is:

1. NmC^-2
2. Nm²C^-1
3. NmC^-2
4. Nm^-2C

• The absolute Electric Potential at a point distant 20 cm from a charge of 2 uc is

1. 9.10²V
2. 9x10³V
3. 9x10⁴V
4. 9x10⁵

• The maximum power (Pout) is delivered to a load resistance R, when the Internal Resistance of the Source is:

1. r =
2. r = R
3. r = 0
4. r R/4

• Which one of the following Resistance is used to Convert a Galvanometer into an Ammeter

1. High Resistance
2. Low Resistance in Series with Galvanometer
3. Shunt
4. High Resistance in Series with Galvanometer

• Cathode Ray Oscilloscope works by deflecting beam of

1. Neutrons
2. Electrons
3. Protons
4. Positrons

• The Energy Stored in an Inductor is given by:

1. LI²
2. L²I/2
3. LI²/2
4. IL²

• Self-Induced emf is sometimes called:

1. Conventional emf
2. Constant emf
3. Back emf
4. Variable emf

• An AC. Voltmeter reads 220 V. its peak value will be:

1. 255 V
2. 340 V
3. 311.12
4. 300 V

• At High Frequency the value or reactance of a capacitor in A.C. Circuit will be:

1. Large
2. In finite
3. Zero
4. Small

• Substances which break just after the elastic limit is reached, are called:

1. Ductile Substances
2. Hard Substances
3. Soft Substances
4. Brittle Substances

• The central Region of a Transistor is called

1. Base
2. Emitter
3. Collector
4. Neutral

• Find the gain of inverting amplifier of external resistance R₁ = 10 K  and R₂= 100 K:

1. -5
2. -10
3. -2
4. 50

• The energy of Photon is given by:

1. mv²/2
2. hƒ
3. V_o^e
4. m_oc²

• If a Particle of mass " m is moving with speed " v" then de - Broglie Wavelength associated with it will be

1. λ = 3h/mv
2. λ = 2h/mv
3. λ = h/mv
4. λ = h/2mv

• The energy of electron of the 4th Orbit in Hydrogen Atom is

1. -2.51 ev
2. -3.50 ev
3. -13.60 ev
4. -0.85 ev

• Pair Production can take place only when energy of radiation is equal and greater than 1.02 MeV, thus correct option is:

1. X-Rays
2. Heat Radiation
3. r – Rays
4. Ultraviolet Rays

• After two half - lives, the number of decayed nuclei of an element are:

1. N
2. N/2
3. N/2
4. 3N/4

SUBJECTIVE PART
SECTION B

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

• Define Electron Volt and prove that I eV = 1.6x 10^-19
• Define Time Constant for RC Circuit. Also draw (q-t) graph for charging capacitor in RC Circuit.
• Electric Lines of Force never cross, why? Explain.
• Describe the force or fumes on a positive point charge when placed between parallel plates
•  With Similar and equal charges
• With opposite and equal charges.
• State Ampere's Law and write it in Mathematical form.
• Suppose that a charge "q" is moving in a uniform magnetic field with a velocity. Why is there no work done by the magnetic force that acts on the charge q?
• Why the Voltmeter should have a very high resistance? Explain.
• Can an Electric Motor be used to derive an Electric Generator with the output from the generator being used to operate the motor? Explain.
• Show that emf and have the same units
• Define Magnetic Flux and Magnetic Flux Density.
• Name four methods to produce induce emf
• Define Self Inductance and its unit.

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

• Define Resistance. Also define its unit.
• Write about any two sources of Current.
• Describe a circuit which will give continuously varying potential.
• Define Instantaneous Value and Peak Value of Alternating Current.
• How the Reception of a Particular Radio Station is selected on your Radio Set?
• Define reactance of a Capacitor. Also write down its formula.
• Define Saturation and Remanence of Hysteresis Loop.
• Define Modulus of Elasticity. Write down its three kinds.
• Define Super Conductors.
• Write down its two technological applications.
• Write down two characteristics of Operational Amplifier.
• What is the effect of Forward and Reverse Biasing of a Diode on the width of depletion region?
• Why a Photodiode is operated in Reverse Biased State?

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

• What are the measurements on which two observers in relative motion will always agree upon?
• Why don't 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?
• What is meant by a Line Spectrum? Explain how line spectrum can be used for the identification of elements?
• Is Energy conserved when an atom emits a photon of light?
• What are Isotopes? What do them in common and what are their differences?
• How can Radio activity help in the treatment of Cancer?
• What do you understand by background radiation? State two Sources of this Radiation.
• A particle which produces more ionization is less penetrating why?

SECTION C
Note: Attempt any THREE questions.
 Q5:

1. What is Potentiometer? How it can be used as
   1.  Potential Divider
   2. Measuring of emf of a cell.
2. Determine the Electric Field at the position  in caused by a point charge q =5.0x10-4 C placed at origin.

Q6:

1. Define Alternating Current Generator. Give its principle construction and working.Derive an expression for induced emf
   
2. A power line 10m high carries a current 200 A. Find the Magnetic Field of the Wire at the ground.

Q7:

1. What is Operational Amplifier? How it is used as Non - Inverting Amplifier?
2. A  coil is connected cross 240V and 180/ Hz, source. How much power does it dissipate?

Q8:

1. Define Strain Energy. Derive a relation Ore Strain Energy in a deformed materials.
2. What is the Mass of a 70 Kg man id a Space Rocket Traveling at 0.8 c from us as measured from Earth?

Q9:

1. Define and explain the Fusion Reaction with examples.
2. Electrons in an X - ray tube are accelerated through a Potential Difference of3000 V. If these electrons were slowed down in a target. What will be the minimum Wavelength of X -rays produced?

Bahawalpur board 2017
  PHYSICS
Inter Part-2
 Time Allowed: 3 Hours
Group 2
Note:-Three are THREE sections in this paper i.e. Section A. B and C. Attempt Section-A on the same paper and return it to the superintendent within the given time. No marks will be awarded for Cutting, Erasing or Overwriting. Marks of Identification will lead to UFM case, Mobile Phone etc. are not allowed in the examination hall.

• The unit of Electron Intensity other than NC^-1 is:

1. VA^-1
2. Vm^-1
3. VC^-1
4. NC

• Force between two similar unit charges placed one meter apart in air is:

1. One Newton
2. 9x10⁹ N
3. 9x10^-9
4. Zero Newton

• A substance having the negative temperature coefficient of resistivity out of the following is

1. Iron
2. Tungsten
3. Carbon
4. Gold

• Two parallel wires carrying the current in the same direction

1. Repel Each other
2. Attract Each other
3. Cancel their field in between them
4. No effect on each other

• S.I. Unit of E is NC^-1 and that of B is NA^-1 m^-1 then the unit of is:

1. m^-1 s^-1
2. ms^-1
3. ms^-2
4. ms

• Lenz's Law deals with

1. Direction of emf
2. Magnitude of emf
3. Direction of Induced Current
4. Resistance

• Electromagnetic Induction obeys Law of Conservation of:

1. Charge
2. Energy
3. Momentum
4. Mass

• The slope of (q - t) curve at any instant of time give:

1. Voltage
2. Current
3. Capacitance
4. Inductance

• An Inductor of 1 Henry inductance has reactance 500 Ohms, then the frequency required is approximately

1. 50Hz
2. 100 Hz
3. 80Hz
4. 120 Hz

• Which one is not a Ductile material:

1. Lead
2. Steel
3. Copper
4. Wrought Iron

• Potential Difference Across Depletion Region in case of Silicon Diode at room temperature is:

1. 0.3 V
2. 0.9 B
3. 0.7 V
4. Zero Volts

• Open Loop gain for Op - Amp is:

1. 106
2. 105
3. 107
4. 103

• The frequency of a Micro - Wave with Wavelength 10 cm can be

1. 300KHz
2. 300uHz
3. 3x10⁹Hz
4. 30KHz

• The existence of Positron in 1928 was predicted by:

1. Andersorr
2. Dirac
3. Chadwick
4. Plank

• Normally Electron can reside in excited state for about:

1. 10^-3s
2. 10^-8s
3. 10^-6s
4. 10⁸s

• When Nitrogen is Bombarded by Alpha Particle, then Nitrogen Nuclie change into Nuclei:

1. Oxygen
2. Carbon
3. Helium
4. Beryllium

• Which pair of Particles belongs la the Hadrons:

1. Photons and Electrons
2. Positron and Electrons
3. Protons and Neutrons
4. Photons and Positrons

SUBJECTIVE PART
SECTION B

Q2: Write short answers to any EIGHT (8) questions.

• The-potential is constant throughout a given region of space. Is the electric field zero or non - zero in this region? Explain.
• Describe the Force or Forces on a positive point charge when placed between parallel plates with i similar and equal charges.
• Do electrons mod to go to region or high potential or of low potential?
• Suppose that a charge q is moving in a uniform magnetic field with a velocity
• How can a current loop be used to determine the presence of a magnetic field in a given 'region of space'?
• Does the induced emf always act to decrease the magnetic flux through a circuit?
• Four unmarked wires emerge from a transformer. What steps would you take to determine the turn’s ratio?
• Define the S.I. unit of Mutual Inductance.
• Why the Voltmeter should have a very high resistance?
• Show Mat t = RC
• Write down the two uses of CRO.
• State the Lenz's Lew.

Q3: Write short answers to any EIGHT (8) questions.

• Why does the Resistance of a conductor rise with temperature?
• Describe a Circuit which will give a continuously varying potential.
• Explain the conditions under which electromagnetic waves are produced from a source.
• Distinguish between Crystalline. Amorphous and Polymeric Solids.
• What is meant by Strain Energy? How can it be determined from Force Extension
• Carbon Silicon and Germanium have four valence electrons. Why Carbon is insulator while Silicon and Germanium are Semiconductors?
• Why charge carriers are not present in the Depletion Region?
• What is the Net Charge on an n-type or a p type substance?
• Define impedance and write its unit.
• Why a photodiode is operated in Reverse Bias State?
• Give two examples Source of current
• Write two properties of series resonance circuit.

Q4: Write short answer to any SIX (6) questions.

• Asia Solid heated and begins to glow, why does it first appear red?
• Does the brightness of a beam of light primarily depends on the frequency of photons or on the number of photons?
• What is the difference between Band Spectra and Line Spectra?
• Define Half Life of a Radioactive Element. What is the Relation between Half Life and Decay Constant?
• If a Nucleus has a half-life of 1 year, does this mean that it will be completely decayed after two years?
• Can pair production take place in vacuum? Explain
• Write down two uses of LASER.
• What do we mean by the term Critical Mass?
• Why are Heavy Elements unstable?

SECTION C
Note: Attempt any THREE questions.
Q5.

1. State and explain Ohm's Law. Also explain the behavior of Ohmic and Non-Ohmic devices with the help of Graphs.
2. Determine the Electric Field at the position  m caused bye point charge q =         5.x 10-6 C placed at origin.

Q6.

1. Define Magnetic Field. Find the value of Force on a Moving Positive Charge in a Magnetic Field.
2. The back emf in a motor is 120 V when the Motor is turning at 1680 rev per min. What is the back emf when the motor turns 3360 rev per min?

Q7.

1. Describe the Flow of Current in n-p-n transistor with the help of circuit diagram. Define-current gain of a transistor.
2. Find the value of the current and inductive reactance when A.C. voltage of 220 Vat 50 Hz is passed through an Inductor of 10H

Q8.

1. Define and explain Compton Effect.
2. What Stress would cause a wire to increase in length by 0.01 % if the Young's Modulus of the Wire is 12x1010 p.a.?

Q9.

1. Define Isotopes. Describe Aston's Mass Spectrograph and how it can be used M separate the Isotopes of an element?