What does 'change only one variable at a time' mean

When ultraviolet light with a wavelength of 254 nm falls on a clean copper surface, the stopping potential necessary to stop emission of photoelectrons is 0.181 v. part a what is the photoelectric threshold wavelength for this copper surface?

A cheerleader lifts his 79.4 kg partner straight up off the ground a distance of 0.945 m before releasing her. the acceleration of gravity is 9.8 m/s 2. if he does this 33 times, how much work has he done? answer in units of j

Sheet-like clouds that make a large layer covering the sky are called cirrus clouds cumulus clouds. nimbus clouds stratus clouds.

What is a nonconformity

a string of fifty 15 ohm christmas tree lights are connected in series. one burns out, they all burn out. calculate the total resistance.

A scientist pours grape juice on three identical white shirts He then uses three different cleaning products on the shirts and measures how clean they get what is the independent variable in this experiment

What part of the atom does nuclear radiation come from?

Why should scientists write reports and give oral presentations of the steps and results of their in investigations?

Which of these rocks are formed by volcanic activity? select the two correct answers. a. marble b. basalt c. limestone d. granite e. sandstone

Which source is most likely an authority on the subject? Dr. Vale, a pediatrician, discusses electrical circuitry on her home-improvement website. Jonah, an amateur cook, teaches his son how to make the best grilled cheese sandwiches.