Question

Question 2 a) Explain the assumptions made in the definition of an ideal gas. What is 10K in °C. (2 marks) b) A velocity selector uses a B-field of 0.8 mt and an E-field of 7 x 10 V mi to select electrons of a certain velocity. What is the kinetic energy of the selected electrons? (2 marks) c) A wire of length 70 cm carrying a current of 700 mA is placed in a uniform magnetic field. When the wire is perpendicular to the field, the force on the wire is measured to be 0.06 N. What is the strength of the field? (3 marks) d) The coil of an electric motor has dimensions 20 cm x 3 cm, contains 200 turns and carries a current of 70 mA. What is the maximum torq when the coil is subjected to a field of 250 mT? (3 marks) Total 10 marks Space to answer Question 2 here

Answer 1

ci) Particles are so small that their volume is 904: 2) ca) Assumptions of the Ideal with the volume occupied negligible compared by the gas- cii) "The positi'cles don't interack, (iii) there is no attractive on repulsive force between them. kinetic euergy of the gay particles is proportional 18° temfperateru civ) the T=10k T Cin Celsius) = (l0 K) – 273.15 2-263.1°C TC) = -263-1ac (b) B=0.8mT E = 7x102 m 0.87 10:37 7x10? V/m OBOOK us 114x10-6 m/s v=B/E elections = 1 mu? Kinetic evige of ele of election <qi koolky = I mu? where m=mas e'. K-E 189.18 10-3'x (1•14610-4)2 Joules KE = 59110

L=70 cm = 0.7 m I = 700 mA = 700 710-3 A F-006 N force on the wire = BIL 0.06 = B X 700X [03X0-7 BE 0.122 T 4 Dineusion of of the electric moter 20 cm x 3cm = 0.2m x 0.03 m N= 200 I = 70 mA = 70X100 A B= 250 m T Toro NBLA 200x&50X103x70X10-3 x 0.280:03 0.021 Nim Torque T= 0.021 Nim