JJC_H1_PHY_P2_Ans

Page 1 of 8 JURONG JUNIOR COLLEGE PHYSICS DEPARTMENT 2016 JC2 Preliminary Examination 8866 H1 Physics Paper 2 Suggested Solutions with Markers’ Comments Qn Suggested solution Remarks 1(a) . ..t 12 01 5 s80 [1] - Sub (b) (. ) (. ) . 2109 8 1 0 1 5 0 1 1 m2h  [1] – Sub [1] – Ans (c) . (. ) (. ) . .. .      1 -1 22 - 1 80 m s 0 9 81 0 15 1 472 m s 80 14 7 2 81 3 m s x y v v v [1] – vy [1] – Ans (d) Both of them have the same vertical acceleration. OR the ball must be targeted at the block. [1] 2(a) As the mass moves upwards at constant speed , the upward force, F, must be equal to the weight of the object, mg. Hence work done on object = Fh = (mg)h By conservation of energy, since Fh is the work done on the object and is equal to the increase in gravitational potential energy, Ep = mgh since its kinetic energy is constant [1] [1] [1] (b)(i) (. ) (. ) (. ) (. ) (. ) (. ) (.) .( . ) . . . 2 By conservation of energy, 10 100 9 81 0 100 9 81 0 50 0 100 1 6 02 0 100 9 81 0 4905 0 128 06 3 m h h h     [1] – Sub [1] – Ans (ii) (. ) (.) (. ) .   -1 By conservation of momentum, 0 100 3 5 0 0 180 19 4 m s v v (. ) (. ) ( ) .   22 By conservation of energy, 110 180 1 94 0 12022 00 7 5 1 m x x [1] - v [1] – Sub [1] – Ans 3(a)(i) . .    3 3 10 1 0 00 1 7 9 56 10 VR I [1] (ii) Into the page/into the plane [1] (b)(i) sin . ( )( . ) .      390 1 12 56 10 0 04 2508 8 2510 N FB I L [1] – Sub [1] – Ans (ii) As the projectile travels along the rail, resistance increases and current I decreases. Therefore force decreases. [1] [1] (iii) To the right. [1]

Page 2 of 8 JURONG JUNIOR COLLEGE PHYSICS DEPARTMENT 2016 JC2 Preliminary Examination 8866 H1 Physics Paper 2 Suggested Solutions with Markers’ Comments Qn Suggested solution Remarks (iv) OR Use stronger voltage/ power supply OR Decrease resistance of track (includes increasing the cross-sectional area of the track). [1] 4(a)(i) The photoelectric current reaches a maximum because it is limited by the rate of emission of photoelectrons which is dependent on the intensity of illumination. Increase in V only increases the acceleration of the photoelectrons but not the rate of emissions of photoelectrons from the metal. [1] [1] (ii) The intensity of radiation is dependent on the rate of incidence of photons. The greater the rate of incidence of photons, the greater the rate of emission of photoelectrons. Since the maximum photoelectric current is dependent on the rate of emission of photoelectrons, increasing the intensity of illumination increases the maximum photoelectric current. Any 2 out of 3 points (b)(i) The current, I = ne where n = number of photoelectrons emitted per second  n = I e = 10 19 4.8 10 1.6 10     = 3.0 × 109 s1 [1] – Ans (ii) Number of photons incident per second N = 2500(3.0 x 109