Two very long parallel wires are a distance d apart and carry equal
currents in opposite directions. What is the locations where the net magnetic
field due to these currents is equal to zero?

The speed of light in a material is 0.50 c. what is the critical angle of a light ray at the interface between the material and a vacuum?

Which bonds are found inside a water molecule

The illuminance of a surface varies inversely with the square of its distance from the light source. if the illuminance of a surface is 120 lumens per square meter when its distance from a certain light source is 6 meters, by how many meters should the distance of the surface from the source be increased to reduce its illuminance to 30 lumens per square meter?