While you will not be required to do any advanced math on the ACT Science section, you may be asked to do basic calculations given information provided in the charts, tables, and passages. Calculation questions may require you to know basic mathematical concepts such as rate of change, differences, and average. Other times, you may be provided with a formula in the passage that you will have to use to answer calculation questions.
Below is a passage from the ACT Science test that is followed by calculation questions:
We will use the information provided in the above passage to answer the following calculation questions.
The passage provides a verbalized mathematical formula that includes work function.
We can write this as an equation:
Where the maximum kinetic energy of the ejected electron.
We can then use the information provided in the table to find values for and .
In Table 1, nine different trials are recorded, each using the same metal but different energy per photon and relative intensity of light.
We can see that the first column, labeled “energy per photon,” shows values of , while the fourth column shows values for .
To find the work function () we can plug the values from the table into the equation. Choose a value that is greater than 0, since the electron may not have any kinetic energy if the energy per photon is below a certain threshold.
In Trials 4-6, the same energy per photon is used with varying relative intensities. However, for each of these three trials, the maximum kinetic energies are the same. Therefore, we can use any of these three data points.
We can also use the data from trials 7-9, and get the same result for the work function.
|Therefore, the answer is F.|
This calculation question asks you to solve for the maximum kinetic energy, given the work function and the energy per photon. These are the same variables we used in our equation from the previous problem.