Two lenses of focal lengths 4.5cm and 1.5cm are placed at a certain distance apart. Calculate the distance between the lenses if they form an achromatic combination.

What happens when chlorine reacts with bromine? a. electrons move from the chlorine atoms to the bromine atoms. b. electrons move from the bromine atoms to the chlorine atoms. c. electrons are shared between the chlorine atoms and the bromine atoms. d. electrons become delocalized among the atoms.

Which types of electromagnetic waves have higher frequencies than the waves that make up ultraviolet light? check all that apply. radio waves infrared light microwaves gamma rays visible light x-rays

Aperson walks first at a constant speed of 4.89 m/s along a straight line from point a to point b and then back along the line from b to a at a constant speed of 2.95 m/s. what is the average speed over the entire trip?