Answer:

Explanation:
Given that,
Pressure, P = 1 atm = 101325 Pa
Area of the square surface, A = 10² = 100 m²
We need to find the mass of vertical column of air. We know that, pressure is equal to the force acting per unit area. So,

So, the required mass of the vertical column of air is
.
Answer:
The photoelectric effect occurs only for frequencies above the cutoff frequency, regardless of the intensity.
Explanation:
The photoelectric effect occurs when light is shined on metals such as zinc beyond a certain frequency (the threshold frequency), which causes electrons to escape from the zinc. The electrons which are fleeing are called photo electrons.
Therefore photo electric effect is
The photoelectric effect occurs only for frequencies above the cutoff frequency, regardless of the intensity.
The best and most correct answer among the choices provided by your question is the first choice or letter A.
Heat transfers associated with phase changes known as latent or "hidden" heats because h<span>eat absorbed or released in a phase change is measured in kJ while temperature is measured in °C.</span>
I hope my answer has come to your help. Thank you for posting your question here in Brainly. We hope to answer more of your questions and inquiries soon. Have a nice day ahead!