Chapter 20 Answer Key: Electrostatic Fields and Forces
Chapter 20: Electrostatic Fields & Forces (Point Charges) – Key
20.1 Electrostatic Forces
1. (i) has extra electrons (ii) 6.25 x 106 e-
2. Repulsive force of 7.2 x 10-4 N
3. Attractive force of 8.24 x 10-8 N 4. 3.0 x 10-3 m
5. 1st excited 5.12 x 10-9 N 3rd excited 3.2 x 10-10 N
6. 9.03 x 1022 m/s2
7. (i) 2.0 x 10-5 m/s2 (ii) 4.03 x 107 e-
8. 1.04 x 1024 m/s2 (electron) ac = 1.41 x 1020 m/s2 (core)
9. d = 1.61 m
10. d = 5.1 m
20.2 Electric Fields (Point Charges)
1. 5.15 x 1011 N/C (away)
2. 3.6 N/C away from Sphere
3. (i) 8.0 x 10-14 N (ii) 2.4 x 1012 m/s2
4. 1.02 x 10-7 N/C upwards
5. (i) 1.6 x 10-15 N (ii) 1.76 x 1015 m/s2
6. 5.4 x 10-5 m
7. 5.6 x 10-5 N/C
8. 8.2 x 10-8 N
9. 7.1 x 108 N/C away
20.3 Hydrogen Atom
1. (i) 1.02 x 10-9 N (ii) 2.18 x 106 m/s (iii) 1.99 x 10-24 N/C
2. Fel = Fc = 0.657 µN
20.4 Electric Potential
1. V = – 27.2 J/C
2. V = 57.5 J/C
3. ∆ V = 24.2 J/C
20.5.1 Deep space research on hydrogen atoms
1. (i) v = 15.9 m/s (ii) 1.15 x 10-28 J