Earth's solar constant a. is actually variable. b. refers to the intensity of solar radiation that reaches Earth's surface. c. is about 0.5 calories per square centimeter per minute. d. must be measured at perihelion. e. must be measured at aphelion.

a. is actually variable.

Explanation:

Earth's solar constant  -

It refers to the total amount of radiations coming from the sun per unit area and per unit time on the surface of the earth , is referred to as Earth's solar constant .

There is an increase of about 0.2 percent during the peak of every 11 year solar cycle  and hence ,

The amount is variable in nature .

Since , the sun is composed of hydrogen gas , which increases to around 10 percent on every billion year .

Hence , from the given question ,

The correct option is a. is actually variable.

vanderwaal's forces of attraction are the electrostatic intermolecular forces that exist in a molecule due to the temporary or permanent dipoles that are developed in a molecule. in , the major intermolecular forces are dipole-dipole interactions as the molecule is polar (bent structure). so the vanderwaal's forces of interaction in between molecules are the permanent dipole-dipole interactions that develop due to the dipole that exists in between the polar h - s bond. the positively charged hydrogen atom is attracted towards the negative end of the dipole that is sulfur of the adjacent molecule. therefore, these forces of attraction are relatively stronger than that of london dispersion forces that exist in non polar molecules.

answer: any goods being imported from another country may be subject to issued by the federal government are tariffs

explanation:  

tariffs are a tax on anything that are imported from abroad. government use them to protect and boost their local industries and the thought is that they encourage consumers to buy local instead of importing and they will hope will protect jobs and economy in the country that implements them