48. Point charges q and Q are positioned as shown. If q = +2.0 nC, Q = -2.0 nC, a = 3.0 m, and b = 4.0 m, what is the clectric potential difference, ?
(A)8.4 V
(B)6.0 V
(C)7.2 V
(D)4.8 V
(E) O V

44. A loop of wire (resistance = 2.0 mΩ) is positioned as shown with respect to a long wire which carries a current. If d = 1.0 cm, D = 6.0 cm, and L = 1.5 m, what current(I) is induced in the loop at an instant when the current in the wire is increasing at a rate of 100 A/s? (A)34 mA(B)30 mA(C)27 mA(D)38 mA(E)0.50 mA

45. A conducting rectangular loop of mass M, resistance R, and dimensions a x b is allowed to fall from rest through a uniform magnetic field which is perpendicular to the plane of the loop. The loop accelerates until it reaches a terminal speed (before the upper end enters the magnetic field). If a = 2.0 m, B = 6.0 T, R= 40 2, and M = 0.60 kg, what is the terminal speed? (A) 1.6 m/s (B) 20 m/s (C) 2.2 m/s (D) 26 m/s (E) 5.3 m/s

46. A conducting sphere of radius R carries an excess positive charge and is very far from any other charges. Which one of the following graphs best illustrates the potential (relative to infinity) produced by this sphere as a function of the distance r from the center of the sphere? (A)(B)(C)(D)(E)

47. A conducting sphere is charged up such that the potential on its surface is 100 V (relative to infinity). if the sphere's radius were twice as large, but the charge on the sphere were the same, what would be the potential on the surface relative to infinity? (A) 50 V (B) 25 V (C) 100 V (D) 200 V (E) 150 V

49. Addition of a metal slab of thickness a between the plates of a parallel plate capacitor of plate separation d is equivalent to introducing a dielectric with dielectric constant x between the plates. The value of x is(A)(d-a)/d(B)d(C)d-a(D)d/(d-a)(E)d/a

50. The magnitude of the magnetic field at point P for a certain clectromagnetic wave is 2.12 µT. What is the magnitude of the electric field for that wave at P ? (c = 3.0 x 108 m/s)(A)636 N/C (B)745 N/C(C) 5.23 µN/C (D) 6.36 µN/C (E)7.45 µN/C

1. 1.25 × 0.25 + 1.222 = ______. (A) 1.5345 (B) 1.535 (C) 1.53 (D) 1.5 (E) 2

2. Over a short interval near time t = 0 the coordinate of a bicycle in meters is given byx(t) = 12t – 4t3 , where t is in seconds. At the end of 1 s, what is the acceleration of the bicycle? (A) 23 m/s2 (B) 15 m/s2 (C) -4 m/s2 (D) -12 m/s2 (E) -24 m/s2

3. A 8000-N trunk is pushed along a level road by two men who apply a total forward force of 1000 N. Neglecting friction, what is the acceleration of the trunk? (Gravitational acceleration g = 10 m/s2) (A) 0.0125 m/s2 (B) 0.125 m/s2 (C) 0.8 m/s2 (D) 1.25 m/s2 (E) 8 m/s2

4. An incompressible fluid of density ρ is in a bucket on the elevator floor accelerating upward with acceleration a. What is the pressure difference between two points in the fluid separated by a vertical distance △h? (Gravitational acceleration is g) (A) ρa△h (B) ρg△h (C) ρga△h (D) ρ(g – a)△h (E) ρ(g + a)△h