Which of the following must be true about an ideal gas that undergoes an isothermal expansion? (there may be more than one correct choice.)
a. no heat enters the gas.
b. the pressure of the gas decreases.
c. the internal energy of the gas does not change.
d. the gas does positive work.

Astudent is given an assignment to demonstrate diffraction. he takes a photograph of a straw in a glass of water. the straw appears bent at the water level. which best describes this example? a) this is a good example of diffraction. b) this is an example of dispersion and not diffraction. c) this is an example of refraction and not diffraction. d) this is an example of reflection and not diffraction.

Which of the following is the result of the nuclear weak force? the instability of large nuclei the repelling force between positively charged protons the structure of the atom certain types of nuclear decay

**urgent** roberto plans to use two transformers to reduce a voltage of 120 v to 4 v. he uses a transformer that has 300 coils in the primary winding and 50 coils in the secondary winding. he has four other transformers, as listed in the table. which transformer should roberto use to have an ending voltage of 4 v? a- w b-xc- yd- z