1. which part of an atom has a negative electric charge? a. protons b. electrons c. neutrons d. both protons and neutrons

There are two-speed cameras, one in an are where the speed limit is 30 km/h and another where the speed limit is 50 km/h. in which will there be a smaller time interval between the photographs? explain your answer.

Matter is needed to transfer thermal energy bya. conductionb. convectionc. radiation d. both a & b.

Why should the wavelength scale of spectroscope be calibrated