Which of the following describes a magnetic field that influence on moving electric charges, electric current, and magnetic materials?   a It is the place where no object may be influenced by a magnet  b It is a region in space marked by visible magnetic lines of force  c It is an area where a magnet can influence other magnets or other magnetizable metals  d It is a space near a magnet where only another magnet may be affected

A magnet's North pole attracts an iron nail. What will happen if the magnet's South pole is brought near the same nail?

What is the direction of a magnetic field if an electron is moving in a circular clockwise direction ?A) leftB) straight away from you (into the page)C) upD) straight towards you (out of the page)E) none of the above

You have discovered a new app on your cell phone that can measure the magnetic field. As you are playing with it, you discover that the magnetic field is significantly stronger than the earth's magnetic field in a particular location of the room. You wonder if it is due to magnetic field do to power lines running in your building. A blue print of the building shows that the nearest line is as shown below. Your sensor reads maximum magnetic field when you are located at point P. Calculate the magnetic field as a function of the current and the distances a and b. Segments BC and AD are arcs of concentric circles. Segments AB and DC are straight-line segments. a A b 120 D