Oh Say, can you c...(where c is the speed of light)

1 D
2 D
3 E
4 E
5 E
6 E
7 B (n1 = 1.2/.8)
8 C
9 D
10 E
11 D (convex mirror is similar to a diverging lens, in that it always produces a virtual image of an object)
12 D (this is a magnifying glass! remember that converging lenses can form both real and virtual images)
13 D
14 D (be sure to draw BOTH the reflected and refracted ray. The angle of the reflected ray will always be 40 degrees from the normal, which means the angle from the surface is 50 degrees. Depending on the index of refraction of the material, the refracted ray will be at most 40 degrees from the vertical, which is an angle of 50 degrees from the surface. Thus the total angle will be between (40 + 50) to (40 + 90 degrees)
15 C

1995B2.
a) R = V^2/P = 24 ohms
b) Energy used = P*delta_t = 6W * (30 days*24 hrs/day*3600 seconds/hr) = 1.6 x 10⁷ J
c) The bulb should be in series with the resistor, and the two should be in parallel with the battery terminals. The toaster should be connected in parallel with the battery so it gets 120 V across it.
d) The bulb needs 12 V across it, which means the resistor must have 108 V across it to add to 120 V. The power of the bulb is 6 W, which by P = IV, means the current must be 0.5 A. Therefore the resistance must be V/I = 108 V/0.5 A = 216 ohms
e)
i. If the variable resistor is increased, the current through the branch will decrease. Since the resistance of the bulb remains the same, the power P = I^2*R will decrease, and the bulb will get dimmer.

ii. The toaster has the same amount of voltage across it, regardless of the resistor. the power will therefore stay the same.

1995B3
a) T directed up, mg down, so T - mg = 0 in equilibrium, and T = mg = 1 N

b)
T sin(th) = Th = ma = (0.1 kg)(5 m/s^2) = 0.5 N
T cos(theta) - mg = 0 with Tv = T cos(theta) = mg = 1 N

c) Constant speed! in equilibrium.

T - mg = 0, so T = Tv = mg = 1 N.
Th = 0 since there are no components of T in the x direction.

d)
Th = ma_x = (0.1 kg)(5 m/s^2)*sin(30) = 2.5 N
Tv = ma_x...

I will post more later, I just realized I am late for an appointment!