# PHYSICS 152

##### University of Hawaii, Manoa Dept. of Physics & Astronomy

Instructor: Michael Nassir
Office: Watanabe Hall, Rm. 426, (808) 956-2922
E-mail: nassir @ hawaii.edu

## ANSWERS to MIDTERM #1 from FALL 2005

Part A

1a. 2.4 MeV
1b. 8.5 x 10^13 mW
1c. 2.0 x 10^6 mm^2
1d. 30. kV/cm
2. F, F, T, T, F, F
3. D
4a(i). D
4a(ii). D
4a(iii). A
4a(iv). D
4b. A
4c. D
4d. 3.34 nC   (V = kQ/r, and solve for Q)

Part B

1a(i). 20.0 ohms
1a(ii). 0.600 A
1a(iii). B
1a(iv). A
1b. connect one 50-ohm and one 100-ohm resistor in parallel; connect the pair in series with the remaining 50-ohm resistor

2a. negative plate on left; positive plate on right
2b. Equally spaced parallel horizontal lines running from right-hand (positive) plate to left-hand (negative) plate.
2c. Two equally spaced parallel vertical lines, spaced one-third and two-thirds of the way between the plates. Left-hand equipotential is at 50 kV; right-hand equipotential is at 100 kV.
2d. B
2e. A, C, and D
2f. v_f = sqrt(2 * |q| * V / m)    Use conservation of energy: -deltaU = deltaK, so: -q*V = (1/2)m*v^2.  OR can use: F = |q|*E, E = V/d; a = F/m; and v_f^2 = v_0^2 + 2*a*d.