I have a quiz and the time is unlimited. This sentence appeared to me. The timer can only start after the setup process is finished.
What does this timer mean? Why does that time appear unlimited, please explain

Imagine that you push on a large rock. at what point does your effort change the rock’s mechanical energy?

Which theory was contradicted by experiments with the photoelectric effect? light spreads out after it passes through a small opening. as soon as light strikes metal, electrons will be ejected. visible light, regardless of color, will cause the ejection of electrons when striking metal. the kinetic energy of ejected electrons depends on the frequency of light that strikes the metal.

Which of the following is an indication that a substance has undergone a chemical change? a. no new product has been formed. b. the color of the substance has not changed. c. the original constitute has not changed. d. the molecular structure has changed.