امتحانات الشهادة الثانوية العامة الفرع : علوم الحياة مسابقة في مادة الفيزياء المدة: ساعتان

Size: px

Start display at page:

Download "امتحانات الشهادة الثانوية العامة الفرع : علوم الحياة مسابقة في مادة الفيزياء المدة: ساعتان"

Stella Alyson Jackson
5 years ago
Views:

1 وزارة التربية والتعليم العالي المديرية العامة للتربية دائرة االمتحانات الرسمية امتحانات الشهادة الثانوية العامة الفرع : علوم الحياة مسابقة في مادة الفيزياء المدة: ساعتان االسم: الرقم: دورة العام 06 اإلستثنائية الخميس 4 اب 06 This exam is formed of three exercises in three pages. The Use of non-programmable calclators is recommended. First exercise: (7 points) Characteristics of a coil The aim of this exercise is to determine the characteristics of a coil. For this aim we set p the circit represented in figre. This series circit is composed of: a resistor of resistance R = 40 Ω, a coil of indctance L and of internal resistance r, a capacitor of capacitance C = 5 μf and an (LFG) of adjstable freqency f maintaining across its terminals an alternating sinsoidal voltage: (t) = = Um cos ωt ( in, t in s). M R B LFG (L, r) + i C q A N We connect an oscilloscope to display the variation, as a fnction of time, of the voltage across the generator on channel (Y) and the voltage BM across the terminals of the resistor on channel (Y). For a certain vale of f, we observe the waveforms of figre. The adjstments of the oscilloscope are: Horizontal sensitivity: ms/div. ertical sensitivity for both channels: /div. Y Fig. Y ) Using the waveforms of figre, determine: a) the period and the anglar freqency of the voltage ; b) the maximm vale Um of the voltage across the terminals of the generator; c) the maximm vale UR(m) of the voltage across the terminals of the resistor and dedce the maximm vale Im of the crrent i in the circit; d) the phase difference between the voltage and the voltage BM. ) Write the expression of the crrent i as a fnction of time. Fig. BM 3) a) Show that the average power consmed by the circit is Paverage = 0.06 W. b) Dedce that r = 8. 4) a) Show that the expression of the voltage across the terminals of the capacitor is: 5 NA sin( t 0. ) ( NA in ; t in s). b) Determine the expression of the voltage AB across the terminals of the coil in terms of L and t. c) Applying the law of addition of voltages and by giving t a particlar vale, determine the vale of L.

2 Second exercise: (7 points) Natre of a collision The aim of this exercise is to determine the natre of a collision between two objects. For this aim, an object (A), considered as a particle, of mass m A = kg, can slide withot friction on a path sitated in a vertical plane and formed of two parts: a circlar part DN and a horizontal rectilinear part. (A) is released, withot initial velocity, from the point D sitated at a height hd = 0.45 m above the horizontal part (Fig.). hd x' D hc (A) C N Fig. (B) M i x The horizontal plane passing throgh MN is taken as the reference level of gravitational potential energy. Take g = 0 m/s. ) Calclate the mechanical energy of the system [(A), Earth] at the point D. ) Dedce the speed A of (A) when it reaches the point N. 3) (A) reaches N and moves along with the same velocity A = A i. Another object (B), considered as a particle, of mass m B = 4 kg moves along the horizontal path from M toward N with the velocity B = i (B in m/s). a) Determine the linear momentm P S of the system [(A), (B)] before collision. b) Dedce the velocity G of the center of inertia G of the system [(A), (B)]. 4) After collision, (A) rebonds and attains a maximm height hc = 0.7 m. a) Determine the mechanical energy of the system [(A), Earth] at the point C. b) Dedce the speed A of (A) jst after collision. 5) Determine, by applying the principle of the conservation of the linear momentm of the system [(A), (B)], the velocity B of (B) jst after collision. 6) Specify the natre of the collision.

3 Third exercise: (6 points) Determination of the volme of the blood of a person by radioactivity In order to determine the volme of the blood of a person, we se the radionclide sodim 4 Na. Given: Planck's constant: h = J.s; Speed of light in vacm: c = 30 8 m/s; Avogadro's nmber: NA = mol - ; Molar mass of sodim 4: M = 4 g; Me = J. Selection from the periodic table: A Sodim 4 Element Florine Neon Sodim Magnesim Alminim 9 Nclide F 0 Ne 3 Na 4 Mg 7 Al Na is obtained by bombarding the sodim Na by a netron. ) Write the eqation of this nclear reaction. ) This reaction is provoked. Jstify. B The sodim 4 is radioactive β - emitter. ) Write the eqation of this disintegration. ) Name the obtained daghter ncles. 3) The disintegration of sodim 4 is accompanied by the emission of a dangeros radiation. a) Indicate the natre of this radiation. b) Indicate the case of the emission of this radiation. c) One of the emitted photons has energy of 3 Me. Calclate the wavelength of the corresponding radiation. C The radioactive constant of sodim 4 is =.80-5 s -. ) At the instant t0 = 0, we inject a soltion containing m0 =.40-4 g of sodim 4 into the blood of a person. Calclate the nmber of nclei N0 of sodim 4 in the injected soltion. ) Calclate, at the instant t = 6 hors, the nmber of sodim 4 nclei remaining in the blood of the person. 3) Sppose that the sodim 4 is niformly distribted in the blood of the person. At the instant t = 6 hors, 0 ml of blood taken from the person contains nclei of sodim 4. Calclate the volme of the blood of the person. 3

4 وزارة التربية والتعليم العالي المديرية العامة للتربية دائرة االمتحانات مشروع معيار التصحيح امتحانات الشهادة الثانوية العامة الفرع : علوم الحياة مسابقة في مادة الفيزياء المدة ساعتان االسم: الرقم: دورة العام 06 اإلستثنائية الخميس 4 اب 06 First exercise (7 points) Part of the Q.a.b.c.d Answer T = 5 div ms / div = 5 ms = 50-3 s 400rad / s 56rad / s. T Um = 3 div. /div = 3 URm = div. /div = ; URm = R Im Im = 0.05A 40 = 0. rad. R lags g by 0. 5 Note i = 0.05 cos (400 t 0. ) 3.a P = UIcos = cos0. = 0.06 W 3.b P = (R+r) I P 0.06 (R + r) = I (0.05) 48 r = 8 4.a d dt C 400C C i C C idt sin(400 t 0. ) sin(400 t 0. ) 4.b di coil= ri + L = 0.4 cos (400 πt dt 0.π) 0 L sin(400 πt 0.π) ; 4.c = NA + AB + BM with R = Ri = cos(400 t 0. ) ; 3 cos (400πt) = 5 sin(400t 0. ) sin(400 t 0. ) + cos (400πt 0.π) 0 L cos(400 t 0. ) For t = 0 : 3 = L L = 0.55 H

5 Second exercise (7 points) Part of Q Answer Note ME(D) = KE(D) + PEg(D) = 0 + maghd = 9J No friction mechanical energy of the system [(A), Earth] is conserved : ME(D) = ME(N) ; 0 + maghd = ½ ma A A = ghd A = 3 m/s. 3- a Linear momentm of the system [(A), (B)] before collision: P S = ma + mb B = ( 3 i ) + [4 ( i )] = i (kg m/s) A 3.b P S = P G = (ma + mb) i = 6. G G G = /3 i = 0.33 i (m/s) 4.a ME(C) = KE(C) + PEg(C) = 0 + maghc = 00.7 = 5.4 J. 4.b 5 6 Conservation of the mechanical energy of the system [(A), Earth] 0 + maghc = ½ ma A A = ghc A = 5.4 =.33 m/s. Conservation of the linear momentm of the system [(A), (B)] : ma A + mb B = i (m/s) (.33 i ) + 4 B = i (.33 i ) + B = i B = i +.33 i = 3.33 i =.66 i (m/s) B The kinetic enegy of the system [(A), (B)] KEbefore = ½ ma A + ½ mb B = J KEafter= ½ ma + ½ mb = ½4.66) = = 0.9 J J A the collision is elastic B.5.5

6 Third exercise (6 points) Part of the Q Answer Note A. 3 0 A. Provoked since it needs an external intervention. B. 4 Z 0 + The laws of conservation give: 4 = A and = Z Z =. B. The daghter ncles is magnesim: 4 Mg B.3.a It is an electromagnetic wave. B.3.b De to the des-excitation of the daghter ncles B.3.c The energy of the photon is : E = c h λ c λ=h E m C. m0 NA No= M = nclei. C. The nmber of nclei remaining in the blood of the person is: N = No = = nclei. Another method : t = n. T ; T = ln/ n = 6/5 N = N 0/ n = nclei C The volme of blood of the person is : L. 3

This exam is formed of three exercises in three pages. The Use of non-programmable calculators is allowed.

This exam is formed of three exercises in three pages. The Use of non-programmable calculators is allowed. 008 وزارة التربية والتعليم العالي المديرية العامة للتربية دائرة االمتحانات امتحانات الشهادة الثانوية العامة الفرع : علوم الحياة مسابقة في مادة الفيزياء المدة ساعتان االسم: الرقم: الدورة اإلستثنائية للعام