1) A dust particle with a charge of 2.9 E−7 C is located 1.5 m from a charged dust cloth. If the force acting on the dust particle from the cloth is 4.29 E−4 N, what is the charge on the cloth? (4 points)

3.7 E−7 C

6.4 E−7 C

7.1 E−8 C

9.2 E−8 C

2) Consider the following diagram.

Diagram showing a thin lens placed at the midpoint of a horizontal axis with a vertical axis running through its center. On either side of the lens, four dots are evenly spaced, two on each side. Between the lens and the first dot on the left, an upward facing arrow is labeled A. A dotted line starts at the dot closest to the lens on the left side of the arrow, and proceeds upward towards the lens, just touching the very tip of arrow A. At the vertical axis of the lens, it connects to a dotted line heading to the left, parallel to the horizontal axis. Another dotted line originates at the center of the lens, at the point where the horizontal and vertical axes meet. That line extends upwards and to the left, just touching the very tip of arrow A, and continuing beyond. The point where that line intersects with the horizontal dotted line is labeled B.

Which of the following would correctly describe the image formed at that point? (4 points)

There would be an upright arrow with the tip at the intersection that is a real image.

There would be an inverted arrow with the base at the intersection that is a virtual image.

There would be an upright arrow with the tip at the intersection that is a virtual image.

There would be an inverted arrow with the base at the intersection that is a real image.

3) If light passing through a medium with an index of refraction of 1.25 enters a new medium with the an index of refraction of 1.25, too, the beam will (4 points)

refract away from the normal in the new medium

refract towards the normal in the new medium

reflect and remain in the first medium

pass through without refracting

4) Two solid bars of copper have different temperatures. The first one has a temperature of 20 °C, while the second one has a temperature of 80 °C. Which of the following statements are correct? Which statement is true? (4 points)

The particles in the 20 °C bar are vibrating faster than the particles in the 80 °C bar.

The particles in the 80 °C bar have a higher average kinetic energy.

The particles in the 20 °C bar are at absolute 0.

The 80 °C bar is going to be slightly shorter than the 20 °C bar.

5) Which of the following were used as evidence for the existence of orbitals? (4 points)

Early experiments showed that energy was quantized.
Light emitted by excited gases showed discrete color lines.
Gases absorb the same colors of light that they emit.

I only

I and II only

I and III only

I, II, and III