Physics - Assignment Solutions

Student mame Stadt number: (Time: 3 hours) PART 1: Below nine (9) statements, State for any cight (of them whether they are True (T) or False (F): (2 marks for each, total 16 marks.): 1) In a transverse wave the disturbed element of the medium moves ima (T direction that is parallel to the wave motion 2) If the intensity of a sound wave is doubled, the intensity level is also doubled 3) The electric field due to a positive charge points outward of the charge. (TF) 4) The equivalent resistance of a parallel combination of resistors is smaller than any of the individual resistance. 5) The total internal reflection can never occur when light travels from a region of lower index of refraction to a region of higher index of refraction (TF) 6) When an object is beyond the center of curvature of a concave mirror the image is always larger than the object. (T) 7) When an object and its image are on the same side of a thin lens, the object and image distances have opposite signs. 8) An object is placed to the left of a converging lens, the image can be upright or inverted. 9) To eject an electron from the surface of a metal, an incident photon must have an energy equal to or greater than the value of the work function of the metal (Ф). choose the right answer from le 16 marka the brackets for only eight (8) of them: (2 marks for each, total PART II: nine dements, Blow nine 1) What happens to the ed of a wave when its frequency is tripled? (A) reduced to one-tied of Cits original value. increases three times. (C) remains uncharpat 2) If the separation berase two charged particles is increased four times, by what factor is the magmode of the electric force reduced? (A) 4 times. do 1/4 times. (C) 1/16 times. 16 times. 3) If a suspended object f is attracted to a positively charged object N. then the object M is negatively charged. (B) either negatively charged or neutral. (C) positively charged 4) Which of the following will decrease the capacitance of a parallel plate capacitor? (There might be more than one choice). moving the plates closer to each other. each other. making the area of the plates (B) moving the plates farther larger. from area of the plates smaller. (D) making the 5) Two resistances R1-30, R2-6 12 are connected in parallel, the equivalent resistance for them is (1)92 (C) 18 2 6) A light travels from a vacuum (n-1) to a medium such water (n>1), which of the following property remains the same? (A) wavelength λ. (B) speed v. frequency f. (D) direction. 7) What fraction of a radioactive sample elapsed? has decayed after four half-life 8) The critical angle for a certain type of glass is 41.8", the index of refraction of this glass is: 9) A convex mirror produces an image that is: (A) 1.45. (B) 1.60. (A) taller than the object . (B) shorter than the object. sometimes taller than the object and sometimes shorter than the object 7) A concave mirror has a focal length of 12 cm. an object placed at a distance of 40.0 em in the front of the reflecting surface of the mirror. What are the properties of the formed image? 8) If a light ray moves from inside the water (n=1.33) toward the water-air interface at an angle of 45° to the normal. Determine the value of the angle of refraction. PART III Below are Ten (10) problems, solve only seven (7) of them. (4 marks for each, total 28 marks.) In figurela wave is travelling amplitude, wavelength, speed and period of the wave if it has a frequency in the positive x-direction. Find the of 16 Hz, knowing that 4x 75.0 см. Ду 20.0 ст.