Physics Intermediate 1 Semester/Term 2017

INTER (PART-I) LAHORE BOARD 2017 PHYSICS Paper I (Subjective Type) Time Allowed: 2:30 Hours Group-I Maximum Marks: 80 NOTE:-Write write question number and its part number on answer book, as given in the question paper. SECTION-I 2. Write short answers to any EIGHT (8) questions. i. (16) Does a dimensional analysis give any information on constant of proportionality that may appear in an algebraic expression? Explain. ii. Suggest one method of reducing the uncertainty in any timing experiment. iii. How many nanosecond in one year? iv. Show that the method E = mc' is dimensionally consistent. ٧٠ Nhore the two different conditions that could make Ã × Ã, = B2 vi. What is the moment of a force about the point lying on the unis of rotation? vii. Define position vector and resultant vector. viii. Uwite what conditions a body and move with uniform acceleration? ix. Explain the circumstances in which the velocity and dand acceleration if of a car: (a) dis core but if is not zorn. (b) dis zore but if is not zorn. x. Is the range of projectite crms for both angles of projection of 30° and 60°? If your answer leyer then prove it? xi. Is 20g ball hits the walt of a squash court with a menzant force of 50 N. If the time of impact of the force is O.Ssec., find the impulse? xii. Explain the difference between laminar flow and turbulent below. 3. Write short answers to any EIGHT (8) questions. (16) 1. When a rocket to returs the atmosphere, its nose cone becomes very bat? Where does this energy comes from? ii. A 70 kg man runs up a long flight of stairs in 4.9 sec. The vertical height of stairs in 4.5 m. Calculate his power output in wats. iii. Differenciate between geyser and aquiler. iv. What is meant by INTEL SAT? At what frequencies the, INTEL SAT-IV operates? v. A body of mosy 'm" is suspended from the celling of an elevator. If the elevator is ascending with acceleration "a", what would be the value of "T" acting on the body? vi. When mud flies off the tyre of moving bicycle, in what direction does it fly? vii. What is driven harmonic cacillator? Give example? viii. Differentiate between five and forced vibrations. ix. If a mass spring system is hung vertically and set into oocillations, why does the motion eventually stop? s. What are the factors on which speed of speod in air depends? xi. Which is richer in hormanics, and athy.. (a) An open organ pipe. (b) A s d v, an pipe xii. Is it possible sor two identical waves traveling in the same d'n ... m ar vig → nug to give rise in semottary wave? 4. Write short answers to any S1°: (6) °p- u a. (12) 1. How will you increas the ' s sing's double slit experiment ii. iii. In Newton's way. ‹ 1) x 1 c i gor circular? How willI I we"vv, sished between un-nolarized and plane polarized light? iv. Aril. i a. cautages use of light as transmiation carrier wave over radio wave carriers. .٧ If - person was looking through a telescope at the full moon, how would the appearance of the moen be changed by covering half of the objective area? vi. Write uses of the spectrometer. vii. Does entropy of a system increase or decrease due to frictien? vili. A thermos flask containing milk as a system is chaken rapidly. Does the temperature of milk rise? ix. What is meant by reversible process? Give it examples. SECTION-I Note: Attempt any THREY questions. (a) State and prove the law of conservation of linear momentum (b) Find the projection of vector a =27-bj-6 in the direction of the vector 7=21-63+4 (a) Explain rotational kinetic enrgy. Find rotational kinetic energy a disc and hoop. (b) A car of mors 800 kg tre illing at 54 kmh- 1 is brought to rest to 60 meters. Find the average retarding force on the ar. What has happened to original kinetic energy. (a) Define pressure of a gas. Prove that P =½N, <=em? > A bity water drapiot of radius 0.010 cm descends through air from a high building. Calculate its terminal velocity. Givn that n for air = 19x10°kgm"'s" and density of water p = 1000 kgm*. 8. (a) What are stationary waver? Describe the stationary waves produced in a stretched string and prove the their frequenzies are quantized. (b) An 8.0 kg body executes SHM with amptitude 30 cm. The restoring force is 60N when the displacement is 30 cm. Find Period and the speed when displacement is 12 cm. 9. (a) What is Michelson's interferometer? Explain its construction and working. (b) A compound microscope has lenath of focal length 1 cm and 3 cm. An object is placed 1.2 cm from the objective lens. If virtual image is formed at 25 cm from the cyc, calculate the separation of lenses?