Inter (Part-II) Sahiwal Board 2014
Physics
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.

• As motor speeds up, the back emf:

(a) Increase
(b) Decreases
(c) Remains constant
(d) Becomes zero

• The average of the background radiation to which we are exposed:

(a) 2 mSv
(b) 1mSv
(c) 3 mSv
(d) 0.01 Sv

• At higher energies more than 1.02 Mev, the dominant process is :

(a) Compton scattering
(b) Pair production
(c) Photo electric affect
(d) Annihilation

• In metastable state, electron resides:

(a) 10^{- 8} sec
(b) 10^--5 sec
(c) 10^{- 3} sec
(d) 10^{- 13} sec

• Which series is visible from the following:

(a) Paschen series
(b) Pfunds series
(c) Lyman series
(d) Balmer series

• Every particle has correponding antiparticle with:

(a) Same mass
(b) Different mass
(c) Opposite charge
(d) Same mass and opposite charge

• Transistors are made from:

(a) Plastics
(b) Metals
(c) Conductors
(d) Dopped semiconductors

• The term transistor stands for:

(a) Transfer of current
(b) Transfer of voltage
(c) Transfer of resistance
(d) Transfer of charge

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

(a) Ferro magnetic
(b) Para magnetic
(c) Dia magnetic
(d) Non magnetic

• Capacitor wil l h ave a large reactance at :

(a) Low frequency
(b) High frequency
(c) Zero frequency
(d) Negative frequency

• In capacotor :

(a) Current leads voltage by л/2
(b) Current leads voltage by л/2
(c) Current leads voltage by л
(d) Both are in phase

• Output wave form of sweep or time base generator is:

(a) Mutual induction
(b) Self induction
(c) Induced induction
(d) Induced emf

• Output wave foem of sweep ot time base genarator is:

(a) Saw tooth wave
(b) Digital wave
(c) Sinsusidal wave
(d) Square wave

• Work done on acharged particle moving in uniform magnetic field is::

(a) Maximum
(b) Zero
(c) Minimum
(d) Negative

• Kirchhoff’first rule is a manifestation of law of conversation of:

(a) Mass
(b) Energy
(c) Charge
(d) Kinetic Energy

• Force per unit charge is:

(a) Electric Flux
(b) Electric Field intensity
(c) Electric Potential
(d) Lorntaz force

• When some dieelectric is inserted between the plates of a capacitor, then capacitance.

(a) Increased
(b) Decreased
(c) Zero
(d) Infinite

Inter (Part-II) Sahiwal Board 2014
Physics
Part II (Subjective)
Time Allowed: 2.10 Hours 
Max. Marks: 83 

Section I

2. Attempt any EIGHT short questions. (8x2 =16)

• How can you identify that which plate of a capacitor is positively charged?
• If apoint charge ‘q’ of mass ‘m’ is released in a non-uniform electric field will it make a rectilinear motion.
• What is time constance of a capacitor resistor circuit an prove that R-C = time constant.
• Prove that lev-1.6x10^-19.
• A plane conducting loop is located in a uniform magnetic field that is directed along x-axis. For what orientation of the loop is the flux a maximum?
• Is it possible to orient a current loop in a uniform magnetic field such that the loop will not tend to rotate? Explain.
• What is the lamp and scale arrangement in galvanometer?
• How can a galvanometer be made more sensitive?
• How would you position a flat loop of wire in a changing magnetic field so that there is no e.m.f in the loop..
• Show that ε and ∆ϕ/∆f have same units.
• Can a D.C. motor be turned in to a D.C genatory? What changes are require to be done?
• Can a step-up transformer increase the power level?

3. Attempt any EIGHT short questions. (8x2 =16)

• Do bends in a wire effects its electrical resistance?
• What is wheatstone bridge? How can it be used to determine an unknown resistance?
• Why does the resistance of a conductor rise with temperature? ?
• A siusoidal current has rms value of 10 A.What is the peak value?
• How does doubling the frequency radio station is selected on your radio set?
• How the reception of a particular radio station is selected on your radio set?
• Distinguish between crystalline, amorphous and polymeric solids.
• What is meant by strain energy ? How can it be determined from the force-extension graph?
• What is meant by hysteresis loss? How is it used in the construction of a transformer?
• What is the net charge on a n-type or a p-type substance?
• The anode of a diode is 0.2 V positive with respect to its cathode.Is it forward biased.
• Why ordinary silicon diodes donot emit light?

4. Attempt any SIX short questions. (6x2 =12)

• Will bright light eject more electrons from a metal surface than dimmer light of the same colour?
• When light shines on a surface, is momentum transferred to the metal surface?
• Why do not we observe a compton effect with visible light?
• Is energy conserved when an atom emits a photon of light?
• If someone accidently swallows an α-source and a β-source, which would be the more dangerous to him? Explain why?
• How can radiology help in the treatment of cancer?
• What are isotopes?
• What is radioactivity?
• What are the advantages of lasers over ordinary light?

SECTION III

Attempt any Three questions. (8x3= 24 )

Question #5.
(a)Describe millikan’s oil drop experiment to determine the charge on an electron.
(b)How many electrons pass through an electric bulb in one minute?If 300 mA current is passing through it.

Question #6.
(a)Define mutual induction and show that emf induced in the secondary is directly proportional to the time rate of change of current in the primary.
(b) What current should pass through a selenoid 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 ?

Question #7
(a). Describe the formation of energy bands in solids Explain the difference amongst electrical behaviour of conductors , insulators and semi-conductors in terms of energy band theory.
(b)Find the value of the current flowing through a capacitor 0.5 μF when connected to a source of 150 V at 50 Hz.

Question #8
(a) .State de-Broglie’s hypothesis, give its formula.Also explain an electron microscope.
(b) In a certain circuit, the transistor has a base current of 40 μA. If the current gain of the transistor is 250, What will be the collector current?

Question #9
(a).What is nuclear reactor? Describe functions of its main parts.
(b) .calculate the longest wavelength of radiation for the Paschen series.

SECTION IV

Attempt any THREE questions. (5x3=15)

Question #10(a).

• How will you check whether the connections of slide wire bridge are correct?
• Write down the equations to find the values of ‘Rs’ (Shunt resistance) and R_H (High resistance)
• In half deflection method value of R is 5400 Ω and S is 120 Ω. Find the resistance of galvanometer.
• Draw the circuit diagram of Wheatstone bridge.
• What do you mean by forward and reverse biase?
• State Ohm's law and give two examples of non Ohmic devices.
• Why the current increases in AC circuit with the increase of capacitance?
• Draw the sybol and truth table of NAND gate?

Explain hoe the resitance of voltmater is found experimentally by plotting the graph between R and 1/V.

( c ) Answer the questions given under the graph.

Graph is plotted between potential difference ‘V’ and charge ‘Q’ on a capacitor.

• Find the slope of the graph.
• Which quantity is represented by the slope? Give its unit.

OR

• Find the slope of the graph.
• Which quantity is represented by the slope? Give its unit.