DG Khan 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.

• A capacitor is perfect insulator for:

1. Alternating current
2. Sparking current
3. Eddy current
4. Direct current

• Presence of dielectric between, two charges always

1. Reduces the electric force
2. Enhances the electric force
3. Does not Effect electric force
4. Doubles the electric force

• The wire of resistance R is cut into two equal parts, the resistance of each part becomes R/2, what happens to its resistivity

1. Becomes double
2. Remains same
3. Becomes half
4. Becomes 4 times

• In CRO which component controls the brightness

1. Filament
2. Grid
3. Anode
4. Deflecting plates

• Galvanometer is sensitive, when C/BAN is

1. Small
2. Zero
3. Large
4. Negative

• "henry" mau be written as:

1. Weber
2. VsA^-1
3. Vs^-1A^-1
4. VsA^-1T^-1

• Induced emf in A.C. generator can be increased by

1. Decreasing area of coil
2. Decreasing magnetic field
3. Increasing area of coil
4. Slowing down speed of coil

• Which consumes small power

1. Inductor
2. Resistor
3. Motor
4. All of them

• When an inductor comes close to a metallic objects its inductances is

1. Decrease
2. Increased
3. Becomes half
4. Becomes 4 times

• In extrinsic semiconductors doping is of the order of

1. 1 atom to 10⁴
2. 1 atom to 10⁸
3. 1 atom to 10³
4. 1 atom to 10⁶

• The size of base of transistor is:

1. 10^-3m
2. 10^-4m
3. 10^-6
4. 10²m

• An expression for current gam of a transistor is given by

1. β =I_B/I_C
2. β =I_B+I_C
3. β =I_C-I_B
4. β =I_C/I_B

• Unit of Plank's constant is same as that of

1. Acceleration
2. Angular momentum
3. Linear momentum
4. Entropy

• The Compton shift is equal to Compton wavelength at an angle of

1. Zero
2. 120°
3. 45°
4. 90°

• For Holography we use:

1. X-rays
2. Laser
3. γ-rays
4. β-rays 

• By emitting B-particle and y- particle simultaneously the nucleus changes its charge by

1. -1
2. +1
3. -2
4. +2

• Energy released by conversion of 1 amu is:

1. 1.6x10^-19ev
2. 1.6x10^-19Mev
3. 200Mev
4. 931Mev

SUBECTIVE PART
SECTION B

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

1. How can you identify that which plate of charged capacitor is positively charged?
2. Comment on the uni-direction of electric line of force.
3. A point charge moves rectilinear path in an electric field. Define the nature of electric field
4. How much is the amount of charge at start of discharging of capacitor and start of charging of a capacitor
5. Two charged particles are projected into a region where magnetic field is perpendicular to their velocities, if the charges are deflected in opposite direction. What can you say about them?
6. Is it possible to orient a current loop in a uniform magnetic field such that the loop will not tend to rotate? Explain
7. Describe the charge in the magnetic field inside a solenoid carrying a steady current-I. if only the number of turns is doubled.
8. What happen to the current of a circuit if a load resistance of the circuit is much less than the voltmeter resistance, the voltmeter is supposed to connect in series to the circuit?
9. A square loop of wire is moving through a uniform magnetic field. The normal to loop is oriented parallel to the magnetic field. Is emf induced in the loop? Comment
10. In a transformer there is no transfer of charge from the primary to the secondary. How is then the power transferred?
11. Considering induced emf produced by A.C. generator of loop resistance R. correlate the instantaneous emf and max emf. Also instantaneous, current and max current
12. Show that induced emf and rate of change of flux has the some unit.

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

1. What is the difference between electromotive force and terminal potential difference?
2. State Kirchhoff s 2nd rule and write its mathematical relation.
3. Is the filament resistance lower or higher in a 500W 220V light bulb than in a 100 W. 220 bulb?
4. Define peak to peak value of A.C. voltage.
5. Define phase of alternating voltage.
6. How many times per second will an incandescent lamp reach maximum brilliant when connected to a 50Hz source?
7. Define polymeric solids and give example.
8. What is the difference between intrinsic and extrinsic semiconductors
9. Define super-conductor
10. How is P-n Junction formed?
11. Why a photodiode is operated in reversed biased state'?
12. Why does the motion of an electron in a n-type substance differ from the motion of holes in a p-type substance?

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

1. A beam of red and a beam of blue light have exactly the same energy. Which beam contains the greater number of photon?
2. Which has lower energy quanta radio wave or x-rays?
3. When does light behave as wave? When does it behave as a particle'?
4. What do we mean when we say that the atom is excited?
5. Can an electron in the ground state of hydrogen absorb a photon of energy 13.6ev and greater than 13.6ev'?
6. What fraction of radioactive sample decays after two half-live shave elapsed?
7. Discuss the advantages of fission power from the point of view of safety. Pollution and resources.
8. It is more difficult to start a fusion 'reaction than a fission reaction, why?
9. What is mass defect

SECTION C

Note: Attempt any THREE questions.
Q5.

1. Define capacitor and capacitance. Find an expression for the capacitance of a parallel plate capacitor when vacuum is present between the plates of capacitor
2. A charge of 90 C passes through a wire in 1 hour and 15 minutes. What is the current in the wire?

Q6:

1. What is transformer? Describe its principle, construction working and types
2. What current should pass through a solenoid that is o.5 m long with 10,000 turns of copper wire no that it will have a magnetic field of 0.4 T?

Q7:

1. Draw the circuit diagram of (R-L-C) series resonance circuit. Discuss its behavior for A.C and also wire down its properties.
2. Find the gain of the circuit as shown in the figure

Q8:

1. Define extrinsic-and intrinsic semi-conductors. How P-type and N-types semi-conductors are formed? Explain
2. X-rays of wave length 22Pm are scattered from a carbon target. The scattered radiation being viewed at 850 to the incident beam. What is Compton shift?

Q9:

1. What is Laser? Describe its working and action.
2. Find the mass defect and binding energy of the deuteron nucleus, the experimental mass of deuteron is 3.3435 x 10^-27Kg.

DG Khan 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.

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

• The idea for electric field lines was proposed by:

1. Henry
2. Michael Faraday
3. Ampere
4. Ohm

• Value of £0 in Coulomm's law is:

1. 9x109Nm2C^-1
2. V8.85x10^-12C²N^-1m^-2
3. 9x10⁹Nm^-2C
4. 8.85x10^-12C²Nm²

• Magnitude of drift velocity is the order of:

1. 10^-6m/s
2. 10⁶m/s
3. 10^-3m/s
4. 10³m/s

• Telsa can be written as:

1. NA^-1m^-1
2. NAm^-1
3. N^-1Am^-1
4. NA^-1m

• Magnetic flux density at a point due to current carrying coil is determined by

1. Ampere’s law
2. Gauss's law
3. Faraday cs law
4. Lenz' slaw

• The jerks hi D.C. motor are created by the use of

1. Armature
2. Commentators
3. Slip rings
4. Source emf

• If 10 A current passes through 100 mH inductor, then energy stored is

1. 100J
2. 5J
3. 20J
4. Zero

• In RLC series circuit, the condition for resonance is

1. XL<XC
2. XL>XC
3. Z>XC
4. XL=XC

• A device which oppose the flow of A.C. is:

1. Resistor
2. Capacitor
3. Inductor
4. None

• The substances in which the atoms do not form magnetic dipoles are called

1. Diamagnetic
2. Paramagnetic
3. Ferromagnetic
4. Crystals

• Automatic functioning of street light can be done by

1. Inductors
2. Capacitors
3. Transistors
4. Comparators

• Which diode works at reverse biasing?

1. LED
2. Photovoltaic cell
3. Photodiode
4. Silicon diode

• Rest mass of photon is:

1. Equal to electron
2. Zero
3. Equal to proton
4. Equal to neutron

• Rest mass energy of electron is

1. 1.02Mev
2. 0.51Mev
3. 931Mev
4. 200Mev

• First spectral series of Hydrogen atom was discovered by:

1. Lyman
2. Rydberg
3. Baimer
4. Paschen

• A device that shows the visible path of ionizing particle is called:

1. GM Counter
2. Solid state detector
3. Scalar
4. Wilson Cloud Chamber

• Which pair belongs to Hadrons:

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

SUBJECTIVE PART
SECTION B

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

1. Comment on electric field in region of constant potential.
2. You follow an electric field line due to a positive point charge. Do electric field and potential increase or decrease?
3. Mention two situations of vector area in electric flux.
4. Center of planetary system is oppositely charged to the rest of planets. How orbits of planets would be modified?
5. Describe the change in magnetic field inside a solenoid carrying a steady current I. if the length of solenoid is doubled?
6. What be the orientation of a current carrying coil in a magnetic field so that torque acting upon the coil is maximum.
7. A conductor contains abundance of charges. What can you conclude about the magnetic field due to stationary charges?
8. If a charged particles moves in a straight line through some region of space, can you say that magnetic field in the region is zero
9. A light metallic ring is released from above into a vertical bar magnet with south-pole to the upside. Does the current flow clockwise or anticlockwise in the ring?
10. Is it possible to change both the area of the loop and the magnetic field passing through the loop and still not have an induced emf in the loop?
11. Does the induced current depend on the resistance of the circuit?
12. Could a step-up transformer increase the power level? Comment.

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

1. State OHM's law and write its formula.
2. Why does the resistance of a conductor rise with temperature?
3. What are the difficulties in testing whether filament of a lighted bulb obeys Ohm's law?
4. Define impedance and write its formula.
5. Define modulation and write its types.
6. How does doubling the frequency affects the reactance of an inductor and a capacitor?
7. Define unit cell and crystal lattice.
8. Define coercivity.
9. What is hysteresis loss?
10. Write two characteristics of an operational amplifier.
11. What is the net charge on an n-type or a p-type substance?
12. What is the base current in a transistor very small?

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

1. What is NAVSTAR navigation system?
2. What happens to the total radiations from a black body if its absolute temperature is doubled?
3. Which photon red, green or blue carries the most (a) Energy and (b) Momentum
4. Write two uses of Laser in medicine.
5. Is energy conserved when an atom emits a photon of light?
6. Define mass Defect and Binding energy.
7. Distinguish between nuclear fission and fusion reaction.
8. What are isotopes? What do they have in common and what are their differences?
9. A particle which produces more ionization is less penetrating why?

SECTION C

Note: Attempt any THREE questions.
Q5.

1. What is electric flux? Explain
2. How many electrons pass through an electric bulb in one minute if the 300 raA current is passing through it.

Q6:

1. Derive an expression for force acting on a current carrying conductor of length L placed in a uniform magnetic field of strength B.
2. A loop of a wire is placed in a uniform magnetic field that is perpendicular to plane of a loop. The Strength of magnetic field is 0.6T. The area of loop begins to shrink at a constant rate of  A A/ At-n 8m²s^-1 What is the magnitude of emf induce in the loop while it is shrinking.

Q7:

1. What is the behavior or A.C. in R-C and R-L series circuit, also find their impedances.
2. The current flowing into the base or a transistor is 100u A Find its collector current, its emitter current. IE and the ratio**** If the value of current gain 3 =100

Q8:

1. What is photoelectric effect? Explain the effect on the basis of quantum theory.
2. A 1 m long copper wire is subjected to stretching force and its length increases by20cm. Calculate the tensile strain and percent elongation which the wire undergoes.

Q9:

1. Define isotopes. Describe in detail, how mass spectrograph is used to determine the isotopes?
2. Compute the shortest wavelength of radiation in Balmer series, what value of n must be used?