The energy levels of hydrogen are____ which means that only certain values of energy are allowed.

The lowest possible energy state of an atom is called the___ state.

A beam of light can be thought of as consisting of a stream of light particles called____.

The portion of the electromagnetic spectrum between wavelengths of approximately 400 and 700 nanometers is called the___ region.

The following data represent the running times of films produced by two motion-picture companies:

$$\begin{matrix} \text{Company} & \text{Time (minutes) }\\ \text{1} & \text{102} & \text{86} & \text{98} & \text{109} & \text{92}\\ \text{2} & \text{81} & \text{165} & \text{97} & \text{134} & \text{92} & \text{87} & \text{114}\\ \end{matrix}$$

Test the hypothesis that the average running time of films produced by company 2 exceeds the average running time of films produced by company 1 by 10 minutes against the one-sided alternative that the difference is less than 10 minutes. Use a 0.1 level of significance and assume the distributions of times to be approximately normal with unequal variances.

The speed at which electromagnetic radiation moves through a vacuum is called the___.

Why does blue light carry more energy per photon than red light?

In the following sets of elements, indicate which element has the smallest atomic size.

d. $\mathrm{N}, \mathrm{O}, \mathrm{F}$

In the following sets of elements, indicate which element has the smallest atomic size.

c. $\mathrm{N}, \mathrm{P}, \mathrm{As}$

In the following sets of elements, indicate which element has the smallest atomic size.

b. $\mathrm{Na}, \mathrm{Si}, \mathrm{S}$

In the following sets of elements, indicate which element has the smallest atomic size.

a. $\mathrm{Na}, \mathrm{K}, \mathrm{Rb}$

Arrange the following sets of elements in order of increasing atomic size.

c. $\mathrm{Pb}, \mathrm{Ba}, \mathrm{Cs}, \mathrm{At}$

Arrange the following sets of elements in order of increasing atomic size.

b. $\mathrm{Rn}, \mathrm{He}, \mathrm{Xe}, \mathrm{Kr}$

Arrange the following sets of elements in order of increasing atomic size.

a. $\mathrm{Sn}, \mathrm{Xe}, \mathrm{Rb}, \mathrm{Sr}$