Answer:
a switch that flicks the light on
The correct answer is B. barometer
Thermometer is used to measure temperature, anemometer is used to measure wind speed, while a hygrometer is used to measure humidity.
1 angstrom = 10^-8 cm
6.5 x 10-4 cm = 65 000 x 10-8 cm = 65 000 angstroms
answer 65 000 angstroms
Remember, Your electric field lines drawn from positive charge (protons) and goes to negative charge (electron)
So, Your Answers would be:
15) B) Positive
16) A) Negative
17) B) Positive
18) A) Negative
19) B) Positive
20) B) Positive
Hope this helps!