What is the frequency of a red light with a wavelength of 6.98 x 10^-6

The answer for #3 is c but i don't know why

Problem #3 (ch. 1, problem 15)the ideal gas law provides one way to estimate the pressure exerted by a gas on a container. the law isí‘ťí‘ť=푛푛푛푛푛푛푉푉more accurate estimates can be made with the van der waals equationí‘ťí‘ť=푛푛푛푛푛푛푉푉â’푛푛푟푟â’푞푞푛푛2푉푉2where the term nb is a correction for the volume of the molecules and the term an2/v2is a correction for molecular attractions. the values of a and b depend on the type of gas. the gas constant is r, the absolutetemperature is t, the gas volume is v, and the number of moles of gas molecules is indicated by n. if n = 1 mol of an ideal gas were confined to a volume of v = 22.41 l at a temperature of 0â°c (273.2k), it would exert a pressure of 1 atm. in these units, r = 0.0826.for chlorine gas (cl2), a = 6.49 and b = 0.0562. compare the pressure estimates given by the ideal gas law and the van der waals equation for 1 mol of cl2 in 22.41 l at 273.2 k. what is the main cause of the difference in the two pressure estimates, the molecular volume or the molecular attractions?

Actual ingredients of lab (the cookies i am actually making) 1/2 cup sugar 1/2 cup brown sugar 1 1/3 stick margarine 1 egg 1/2 tsp salt 1 tsp vanilla 1/2 tsp baking soda 1 1/2 cup flour 1 1/3 cup chocolate chip can you answer the questions below ? discussion 1. suppose you are given the following amounts of ingredients: 1 dozen eggs 24 tsp. of vanilla 1 lb. (82 tsp.) of salt 1 lb. (84 tsp.) of baking soda 3 cups of chocolate chips 5 lb. (11 cups) of sugar 2 lb. (4 cups) of brown sugar 1 lb. (4 sticks) of margarine a. for each ingredient, calculate how many cookies could be prepared if all of that ingredient were consumed. (for example, the recipe shows that using 1 egg- with the right amounts of the other ingredients- yields 24 cookies. how many cookies can you make if the recipe is increased proportionately for 12 eggs? ) b. to determine the limiting reactant for the new ingredients list, identify which ingredient will result in the fewest number of cookies. c. what is the maximum number of cookies that can be produced from the new amounts of ingredients?