Physics model exam.pdf

Grade 12 Physics model examination AMHARA REGINAL STATE, SOUTH-WOLLO EDUCATION OFFICE, DESSIE GRADE 12 PHYSICS MODEL EXAMINATIONS GENERAL DIRECTIONS THIS BOOKLET CONTAINS PHYSICS EXAMINATION. IN THIS EXAMINATION, THERE ARE A TOTAL OF 50 MULTIPLE CHOICE QUESTIONS AND EACH HAS...

Grade 12 Physics model examination AMHARA REGINAL STATE, SOUTH-WOLLO EDUCATION OFFICE, DESSIE GRADE 12 PHYSICS MODEL EXAMINATIONS GENERAL DIRECTIONS THIS BOOKLET CONTAINS PHYSICS EXAMINATION. IN THIS EXAMINATION, THERE ARE A TOTAL OF 50 MULTIPLE CHOICE QUESTIONS AND EACH HAS 0.8 MARKS. CAREFULLY SELECT THE BEST ANSWER AND BLACKEN ONLY THE LETTER OF YOUR CHOICE ON THE SEPARATE ANSWER SHEET PROVIDED. FOLLOW THE INSTRUCTIONS ON THE ANSWER SHEET AND THE EXAMINATION PAPER CAREFULLY. USE ONLY PENCIL TO MARK YOUR ANSWERS. YOUR ANSWER MARK SHOULD BE HEAVY AND DARK, COVERING THE ANSWER SPACE COMPLETELY. PLEASE ERASE ALL UNNECESSARY MARKS COMPLETELY FROM YOUR ANSWER SHEET. YOU ARE ALLOWED TO WORK ON THE EXAM FOR 2:30 HOURS. WHEN TIME IS CALLED, YOU MUST IMMEDIATELY STOP WORKING, PUT YOUR PENCIL DOWN, AND WAIT FOR FURTHER INSTRUCTIONS. ANY FORM OF CHEATING OR AN ATTEMPT TO CHEAT IN THE EXAMINATION WILL RESULT IN AN AUTOMATIC DISMISSAL FROM THE EXAMINATION HALL AND CANCELLATION OF YOUR SCORE (S). PLEASE MAKE SURE THAT YOU HAVE WRITTEN ALL THE REQUIRED INFORMATION ON THE ANSWER SHEET BEFORE YOU START TO WORK ON THE EXAMINATION. DO NOT TURN THIS PAGE UNTIL YOU ARE TOLD TO DO SO. SOUTH WOLLO EDUCATIONAL 2016E.c Page 1 OFFICE  Grade 12 Physics model examination You may refer the information given below when you work on some of the questions. Quantities Value Quantities with Value Quantities withValue 2 Acceleration due to gravity 10m/s Sin 300=cos 600= 0.5 α steel =12x10-6/0c Mass of proton 1.67x10-27kg Sin 370=cos 530=0.6 α brass= 19X10-6/C0 Mass of electron 9.1x10-31kg Sin 450=cos 450=0.7 Cwater = 4200J/kgC0 Charge of proton & electron 1.6x 10-19C Sin 600=cos 300=0.9 C copper = 390J/kgC0 Earth’s magnetic field 5x10-5T Sin 900= cos 00=1 L v(water) = 2.26X106J/kg Permittivity of free space(µ0) 4π x10-7Tm/A Sin 00= cos 900= 0 Lf(water)=3.34x105J/kg Permeability of free space(ἐ0) 8.85 x10-12 Nm2 /C Cos370=sin 530= 0.8 ρ(water) = 1000kg/m3 Electric force constant(k) 9x109Nm2/c2. SOUTH WOLLO EDUCATIONAL 2016E.c Page 2 OFFICE  Grade 12 Physics model examination 1. Given three vectors with their positions , 30° West of South, Then the magnitude of the resultant vector is: A. 2.5 B. 3.5 C. 3.04 D. 3 2. A certain wave is characterized by the wave length λ, frequency f and wave speed v. As wave travels from one medium to another one, it gets refracted. Which of these characteristics of the wave are changed due to refraction? A. λ, f and v B. λ and f C. λ and v D. f and v 3. A man walks for 1 minute at a speed of 2m/s and then runs for 2minute at 5m/s along a straight road. What is the average speed of the man? A. 4m/s B. 3.5m/s C. 4.5m/s D.3m/s 4. A force of 200N is needed to pull a 52Kg box across the horizontal surface at constant speed. Then the coefficient of friction between the floor and the box is: A. 0.33 B. 0. 18 C. 0.25 D. 0.40 5. Which statement about the force on a charged particle placed in a magnetic field is TRUE? A. A magnetic force is exerted only if the particle is moving. B. The force is a maximum if the particle is moving in the direction of the field. C. The force causes the particle to gain kinetic energy. D. A magnetic field always exerts a force on a charged particle 6. A train starting from rest moves with constant acceleration and covers 400m in 10 seconds. Where was the train 2 seconds after it began its motion? A. 32m B. 40m C. 16m D. 26 7. Which one of the elements gives N-type semiconductor when they are doped with a pure semiconductor? A. arsenic, indium, antimony C. boron, indium, antimony B. Phosphorus, arsenic, antimony D. Aluminum, boron, indium , 8. According to Archimedes principle, if a solid object floats, the volume of displaced water is equal to the volume of A. The portion of the object that is submerged. C. Half of the object. B. The portion of the object that is above the water. D. The whole object 9. Suppose an object of mass 10kg is hung with two cords as show in the figure below. What is the value of the tension T1 and T2 respectively? A. 48.4N, 64.5N B. 25.5N, 74.5N C. 60N, 80N D. 45N, 55N SOUTH WOLLO EDUCATIONAL 2016E.c Page 3 OFFICE  Grade 12 Physics model examination 10. Which of the following is NOT correct about semiconductor diodes? A. The characteristics of ideal diodes are those of a switch that can conduct current in only one direction B. The characteristics of ideal diode are those of store electric charges at lower potential C. Act as a short circuit for the region of conduction. D. Act as an open circuit in the region of non-conduction. 11. A box of mass m placed on a frictionless inclined plane which slanted at an angle of 300 above the ground is pulled by a force of 350N up the inclined parallel to the plane. If the box accelerates at 5m/s 2, what is mass of the box? A. 70 kg B. 40 kg C. 35 kg D. 55 kg 12. The intensity of sound wave 1m away from a speaker is I. What will be the intensity twice as far away from the speaker? A. 1I B. 2I C. 1I D. 4I 2 4 0 13. Water at 50 c can be obtained by mixing A. 1kg of ice at 00c and 1kg of steam at 1000c. C. 1kg of ice at 00c and 1kg of water at 1000c. B. 1kg of water at 00c and 1kg 0f steam at 1000c. D.1kg of water at 00c and 1kg of water at 1000c. 14. A body covers half of its journey with a speed of 20m/s and the second half with a speed of 30m/s. What is the average speed during the whole journey? A. 12m/s B. 24m/s C. 25m/s D. 50m/s 15. When a bimetallic strip made of two metals ‘X’ and ‘Y’ is cooled, the strip is seen to bend towards metal ‘X’ as shown below. The reason for this to happen A. metal ’X’ is stronger than metal ‘Y’ B. metal ‘ X’ is weaker than metal ‘Y’ C. metal ‘Y’ has greater coefficient of expansion than metal ‘X’ D. metal ‘X’ has greater coefficient of expansion than metal ‘Y’ 16. Find the magnitude of the vector C that satisfies the equation 2A − 6B + 3C = 2j , where A = i − 2 ^ and B = − J + 3 2 A. i+ B. -2j - 2 C. - 2i - 4 D. -2j + 3 3 3 3 17. You point a rifle horizontally toward the center of the paper target 100m away from you. If the muzzle speed of the bullet is 1000m/s, where will it strike the target from the center? A. 5cm below the target C. 10cm below the target B. 5cm above the target D. 10cm above the target SOUTH WOLLO EDUCATIONAL 2016E.c Page 4 OFFICE  Grade 12 Physics model examination 18. A stone is thrown into the air at an angle above the horizontal and feels negligible air resistance. Which graph in the figure below best describes the stones speed V as a function of time? A. B. C. D 19. We know that turning faucet’s controls knob alters the flow rate of water coming out from the faucet. Which electronics device analogous to a faucet? A. Capacitor B. Diode C. Transistor D. Transformer 20. If the distance of the planet from the sun is five times that of the earth, what is the period of revolution of the planet around the sun? √ √ 21. Suppose a small object of mass m carries a charge Q and is suspended by a thread between the vertical plates of parallel plate capacitor. The plate separation is d. If the thread makes an angle ϴ with the vertical, what is the potential difference between the plates? mgd sin mgd tan8 mgQ tan8 mgQ sin8 A. Q B. Q d D. d 22. All of the following are C. application of microwaves Except A. Transmission of television signals. C. wireless telephone transmission. B. SONAR communication of submarines. D. FM radio broad casting 23. Three capacitors C1, C2 and C3 are connected as below, C1= 2µF and C2= 5µF. If the potential drop across C1 is 40v and the potential drop across C2 is 10v, what is the equivalent capacitance? A. 2µF B. 1.6µF C. 3µF D. 3.9µF 24. A battery has an emf of 30v and internal resistance of 0.5Ω. If a current of 10A flows through the circuit, what is the value of load resistor? A. 2 Ω B. 3Ω C. 2.5Ω D. 3.5 Ω 25. In an electric circuit shown in the fig below, R2 is a rheostat whose resistance can be varied the ammeter reading will A. Increase with increasing R2 B. Decrease with increasing R2 C. Increase with decreasing R2 D. Remain the same SOUTH WOLLO EDUCATIONAL 2016E.c Page 5 OFFICE  Grade 12 Physics model examination 26. The working of a transformer is based on A. Motor effect B. photoelectric effect C. electromagnetic induction D. thermionic emission. 27. The position of a certain particle moving along the X axis is given by the equation X (t) = 6 + 8t + 2t2. Where x is measured in meter and t is measured in second. What is the average acceleration b/n 0 second and 2 second? A. 2m/s2 B. 4m/s2 C. 3m/s2 D. 1m/s2 28. Suppose a magnetic field = 0.4 is out of the page of this paper as shown below. The wire having a length of 3cm carries a current of 30A. The magnitude and direction of the force exerted by the external magnetic field is: A. 0.83N, out of the page of this paper C. 0.36N, downward B. 0.36N, upward D. 0.83N, into the page of this paper 29. What is the nature of the image formed by the concave mirror when the object is located between focal point and the pole of the mirror? A. Real, inverted and magnified C. Real, inverted and diminished B. virtual, erect and magnified D. Virtual erect and diminished 30. In a certain measurement of a physical quantity, the repeated readings are close together but they are quit far from the true value. Thus the measurements are A. Precise but inaccurate C. accurate and precise B. Accurate but imprecise D. inaccurate and imprecise 31. Suppose = 2J + and = + 2J are given, what is the unit vector perpendicular to both vector and ? A. 2 − J + 2 B. 1 ( 2 − J + 2 C. −2 + J − 2 D. 1 (−2 + J − 2 3 3 32. Suppose a jet plane lands with a speed of 100m/s and slows down at 5m/s every second and comes to rest. If the runway is 0.8km long, which one of the following is TRUE about the landing of the jet? A. It covers a distance of 1.8km and do not land on this airport. B. It covers a distance of 1.8km and can land on this airport. C. It covers a distance of 0.2km and land on this airport. D. It covers a distance of 1km and do not land on this airport. 33. Suppose a highway curve is banked at angle 370 and a car is travelling at 15m/s can round the curve without skidding. If there is no friction between the tire of the car and the ground, what is the radius of the curve? A. 9.0m B. 30.0m C. 16.9m D. 12.0m SOUTH WOLLO EDUCATIONAL 2016E.c Page 6 OFFICE  Grade 12 Physics model examination 34. Suppose Two masses m1 and m2, are connected by a cord and arranged as shown In the diagram with m1 sliding along on a frictionless surface and m2 hanging from a light frictionless pulley , what would be the mass of the falling mass m2,if both the sliding masses m1 and the tension T1 in the cord were known? 1 A. B. m1( g–T ) C. m1( T–g ) D. Tm1 g–1 g gM1–T gm1–T 35. A 2kg block starts from rest on the positive x axis 1m from the origin and thereafter has an acceleration given by a = (4i-6j) m/s2. What is its angular momentum about the origin at the end of 3sec? A. 72kgm2/s kˆ C. ‒72 kgm2/s kˆ B. 36kgm2/s kˆ D. ‒ 36 kgm2/s kˆ 36. An ice skater is spinning fast with her arms tight against her body, when she extend her arms, which of the following is NOT true? A. She increases her moment of inertia. B. She decreases her angular velocity. C. Her moment of inertia remains constant. D. Her total angular momentum will remains constant. 37. A system consists of three particles of masses located as shown below. Which one of the following alternatives can be the center of mass of the system? A. 38. A uniform ladder of length L and the mass of the ladder is m rests against a smooth, vertical wall. The coefficient of static friction between the ladder and the ground is µs. The minimum angle at which the ladder does not slip expressed as mg µs µs 1 A. cos = B. cos = C. tan = D. tan = µs mg 2 2µs SOUTH WOLLO EDUCATIONAL 2016E.c Page 7 OFFICE  Grade 12 Physics model examination 39. A needle floats on the surface of water because of A. Lighter weight C. Adhesive force B. Surface tension D. Viscosity 40. An object of mass m at rest explodes in to two unequal masses 1m and 2m. If the 1mass moves to the right 3 3 3 2 with speed of 20m/s, what is the velocity acquired by the mass? 3 A. 10m/s to the right C. 40m/s to the right B. 10m/s to the left D. 40m/s to the left 41. Which one of the following is NOT true about ideal fluid flow A. The fluid is non-viscous C. The fluid is compressible B. The flow is steady D. The flow is irrotational 42. A sample of an unknown material weighs 300 N in air and 200 N when submerged in alcohol solution with a density of 700kg/m3. What is the density of the material? A. 1050 kg/m3 B. 2100kg/m3 C. 466.7kg/m3 D. 233.3kg/m3 43. Which one is INCORRECT explanation about MRI? A. Hydrogen proton in our body acts as a tiny magnet oriented randomly. B. MRI image depends upon the presence of electrons in the body. C. In our body Protons are free hydrogen atom without electrons. D. MRI uses the movement of small magnets within a magnetic field to generate an image. 44. Suppose a projectile is launched with initial velocity of(8 + 6 ). Then the ratio of the range of the projectile to the maximum height of the projectile is: A. 16:3 B. 3:16 C. 1:6 D3:4 45. A flat loop of wire consisting of a single turn of cross-sectional area 8cm2 is perpendicular to a magnetic field that increases uniformly in magnitude from 0.5T to 2.5T in 1s. What is the resulting induced current if the loop has a resistance of 2Ω? A. 16 × 10–4A B. 8 × 10–4 A C. 4 × 10–2A D. 12 × 10–4A 46. Suppose an electromagnetic induction takes place due to the relative motion of the magnet with respect to the wire as shown in the figure below. Which of the following is TRUE about the direction of the induced current in the resistor R when the bar magnet is moved to the left? 47. One of the following is TRUE about doping of semiconductors A. Diffused impurities with five valence electrons are called donor atoms. B. Diffused impurities with three valence electrons are called donor atoms. C. Diffused impurities with five valence electrons are called acceptor atoms D. In a p-type material the electron is the majority charge carrier and the hole is the minority charge carrier. SOUTH WOLLO EDUCATIONAL 2016E.c Page 8 OFFICE  Grade 12 Physics model examination 48. Water following through hose having diameter 1cm at a speed of 1m/s. if water is to emerge at 25m/s, then the diameter of the nozzle is: A. 0.2cm B. 0.1cm C. 0.02cm D. 0.01cm 49. Suppose a diode is connected in a Reverse Bias condition, which one is NOT correct about the junction? A. Positive voltage is applied to the p-type and negative voltage is applied to the N-type material. B. The depletion layer grows wider due to a lack of electrons and holes C. High potential barrier is created thus preventing current from flowing through the semiconductor. D. Practically zero current flows through the junction diode with an increase in bias voltage 50. One of the following logic circuit symbols represent the truth table given below. A B Z A. 0 0 1 B. 0 1 1 1 0 1 C. 1 1 0 D. “The End” SOUTH WOLLO EDUCATIONAL 2016E.c Page 9 OFFICE