The substance is an element off of the periodic table.
Given the wavelength of the yellow light (700 nm. in this case) we can find the frequency
<span>by dividing the speed of light c by the wavelength w, that is: f = c/w and we know that </span>
<span>c is equal to 2.998 * 10**8 meters per second. </span>
<span>So the frequency f = (2.998 * 10**8) / (7.0 * 10**-7) = 4.283 * 10**14 cycles per sec. </span>
<span>(or Hz.) Since the threshold frequency of Cs is 9.39 * 10**14 Hz, the red light doesn't </span>
<span>have a high enough frequency (or energy) to cause electron emission. </span>
<span>Hope this answers your question.</span>
Answer:
D. An acid accepts an electron pair from a base.
Explanation:
acorroding to lewis
- an acid is a compound which accepts a pair of electrons from base .
- a base is a compound which donates a pair of electron to acid .
