Calculate the force between two small charged spheres having charges of 3×10−7 C and 4×10−7 C placed 20 cm apart.

Which describes an image that can be produced by a concave lens? the image is real and smaller than the object. the image is virtual and larger than the object. the image is virtual and smaller than the object. the image is real and larger than the object.

What type of light does this light bulb produce most (i. e. at what wavelength does the spectrum have maximum intensity)?

To do work, this truck uses energy stored in chemical fuel and an electrical battery. how much total energy does this truck put out?