Rawalpindi board PHYSICS 2012
Inter part 2
Physics
Note:Pour possible answers A, B, C and D to each question are given. The choice which you think is correct that circle in front that question with Marker or Pen ink. 'Lining or filling two or more circles 'will result in zero mat k in that question. Write the letter A, B. C or D in the column.(write correct "option) against each question also. If there k a contradiction in the bubble and hand written answer, bubble option will be considered correct.

• The smallest possible charge which a particle can have is:

1. 6 x 10-1^-19C

• Which of the following units is different from the other?

1. Volt

• If the current through a resistance is halved, then the:

1. Power is halved
2. heat dissipated is halved
3. Potential difference is halved
4. resistance in soubled

• Charge in motion produces:

1. magnetic field

• A charged particle moving in a magnetic field experiences a force give by:

• The value of shunt resistance required to convert a galvanometer into ammeter is:

1. R_s = I_g^R_g / I –I _g

• Henry is the unit of:

1. Mutual inductance.

• The energy stored in an inductor is given by:

1. U_m = ½ LI²

• Reactance of a capacitor is given by:

1.  Xc = 1/2

• Amorphous solid has a:
• disordered structure

• A p-type semi conductor is electrically

1. Neutral

• The voltage gain of an inverting amplifier. is:
• R₂ / R₁

• The momentum of a photon of frequency f is:

• In Compton scattering the value of Compton's shift equals Compton's wave length of electron when X-ray is scattered at an angle of

1. 90°

• The value of Rhdberg's constant is:

1. 0974 x 10⁷m^-1

• ₉₀TH ²³⁴ decays by emitting a beta particle to form:

1. ₉₁Pa²³⁴

• Which is not the nuclear radiation?

1. X-rays "

Q2: Write short answers.

1. Why electric lines of force never cross?
2. How can you identify that which plate of a capacitor is positively charged?
3. Define election volt & show that 1.ev = 1.6 x 10-19
4. Do bend in a wire affect its electrical resistance? Explain.
5. is filament resistance lower or higher in a 500w, 200v lighted bulb than in a 100w, 220v bulb?
6. Define resistance and its SI units?
7. What should be the orientation of a current carrying coil in a magnetic field so that torque acting upon the coil is:
   1. Maximum
   2. Minimum
8. Why the resistance of an ammeter should be very low?
9. Define magnetic flux and give its two units?
10. Four unmarked wires emerge from a transformer.
11. What steps would you take to determine the turns ratio?
12. Does the Induced emf in a circuit depend on the resistance of the circuit?
13. In a certain region the earth's magnetic field points vertically down. When a plane files due north, which: wingtip is positively charged?

Q3: Write short answers.

1. Define self inductance and its SI unit?
2. How many times per second will an incandescent lamp reach maximum brilliance when connected to a 50 Hz source?
3. How the reception of a particular radio station is selected on your radio set?
4. Describe four propertiestratseries resonant circuit?
5. Explain the electricaltehavieur of conductors in terms of energy band theory?
6. Differentiate between elastic deformation and plastic deformation?
7. Explain what is-Curie temperature?
8. Find the Owen gain of a transistor whose collector Cur entity 100 mA and base current is 100pA?
9. How operational amplifier acts as comparator?
10. Why is base current in a transistor small?
11. We cannot observe the Compton Effect with visible light. Why?
12. A beam of red light and a beam of blue light have exactly the same energy. Which beam contains the greatest number of photons?

Q4: Write short answers.

1. Does time dilation mean that time really passes more slowly in moving system or that it only seems to pass more slowly?
2. The rest mass of a photon is zero, what can you say about its momentum?
3. Can the electron in ground state of hydrogen atom absorb a photon of 13.6 ev and greater than 13.6 ev?
4. Explain why laser action could not occur without population inversion between atomic levels?
5. Under what conditions Ka & Ku X-rays are emitted?
6. What is the difference in the action of and [I particles for producing ionization?
7. What factors make a fusion reaction difficult to achieve?
8. What are the particles inside a proton?
9. Describe steps of P-P reactions of nuclear fusion is sun?

Q5(A) What is Wheatstone bridge? Explain it with labeled diagram and show howls it used to find the unknown resistance?
(B) Determine the electric field at a position F = (41. + 31) m caused by a point charge q. = 5.0 x 10-6C placed at the origin?

Q6(A) What is motional ernf? Derive a relation for it?
(B) How fast must a proton Move in a magnetic field of 2.50 x 10-3T such that the magnetic force is equal to its weight?

Q7(A) What are energy bands? Differentiate between insulator, and semi conductor on the basis of band theory Of solids? '
(B) Find the value of current flowing through a capacitance 0.5pF when connected to a source of 150v at 50Hz.

Q8(A)Draw the circuit diagram of full wave rectifier. Discuss the working of semi-conductor diode as full wave rectifier?
(B) What is de-Broglie wave length of an electron whose K.E. is 120e.v. (h = 6.63 x 1.0-4J.)?

Q9(A) What are the basic forces of nature? Also explain the basic building blocks of matter?
(B) Calculate the longest wavelength of radiation is Paschen series?