9) [2 marks] During a thunder storm, the cloud and the ground is as if become a parallel plate capacitor. Lightning will occur when the electric field between the cloud and ground exceeds the dielectric breakdown of the air (3 x 106 Vm ). If the cloud is 1000 m above the ground, determine the electric potential difference between the cloud and ground (a) 3.0 Giga V (b) 3.5 Giga V (c) 3.7 Giga V (d) 4.0 Giga V 10) [1 mark] Two point charges -q and +q are located as shown in the Figure below. What is the direction of electric field at point A? (a) A (b) B (c) C A A -9 B C B +9 V D C D TERBUKA