When was the first ozone hole discovered

Which statement best describes resistance? resistance is a. how well a current will flow in a material and is measured in volts. b. how well a material conducts an electrical charge and is measured in ohms. c. the ability of a material to attract a positive charge to create a current. d. the ability of a material to repel neutral charges and is measured in ohms.

If the area of a square has increased by a factor of 16, by how much has each side increased?

Why do atoms emit energy of only specific wavelengths