The average diameter of the Milky Way galaxy is about 115,000 light-years. Which choice below correctly expresses this in scientific notation? (1)

$$1 \times 10 ^ { 5 } \text { light-years }$$

(2)

$$115 \times 10 ^ { 5 } \text { light-years }$$

(3)

$$1.15 \times 10 ^ { 5 } \text { light-years }$$

(4)

$$2.3 \times 10 ^ { 10 } \text { light-years }$$

If a light bulb manufacturing company wants to estimate, with 95% confidence, the mean life of light emitting diode (LED) light bulbs to within $\pm$ 400 hours and also assumes that the population standard deviation is 1,500 hours, how many LED light bulbs need to be selected?

Given that the speed of light equals $3.0 \times 10^8 \mathrm{~m} / \mathrm{s}$ and the wavelength of light is $389 \mathrm{~nm}\left(389 \times 10^{-9} \mathrm{~m}\right)$, calculate the frequency of the light.

For both converging and diverging lenses, discuss how the focal length for red light differs from that for violet light.

What is light scattering?

Distinguish laser light from the light emitted by an ordinary lightbulb in as many ways as you can.

What is the speed of light?

Identify the italicized word or phrase. Write $P$ for participle, $G$ for gerund, or $I$ for infinitive.

The photograph mounted in the silver frame was my mom's favorite birthday present.

Repeat the construction from 8a by selecting an arbitrary point $A$ on the curve $y=x^3$. Show that the two areas R and S are always related in the same way.

Which has the higher frequency, red light or violet light? Which has the longer wavelength? Which has the greater energy?

Complete the sentence in a way that shows you understand the meaning of the italicized vocabulary word.

Celerity of work was important to the construction crew because ...

Light is an electromagnetic wave and travels at a speed of 3.00 × 10^8 m/s. The human eye is most sensitive to yellow-green light, which has a wavelength of 5.23 × 10^-7 m. What is the frequency of this light?

Find the frequency of the same light when inside diamond of monochromatic light having a wavelength in air of 530 nm.

Visible light having a wavelength of $6 \times 10^{-7}$ $\mathrm{m}$ appears orange. Compute the frequency and energy of a photon of this light.