Lalasa asks Mackenzie if she knows what current is. Which of her responses is correct? "A device that converts stored chemical energy into useful electrical energy." "The flow of electric charges through a piece of material." "The work that would have to be done, per unit charge, against a static electric field to move a charge between two points." "An object's opposition to the flow of charge carriers."

When a vertical beam of light passes through a transparent medium, the rate at which its intensity i decreases is proportional to i(t), where t represents the thickness of the medium (in feet). in clear seawater, the intensity 3 feet below the surface is 25% of the initial intensity i0 of the incident beam. what is the intensity of the beam "10" feet below the surface? (give your answer in terms of i0. round any constants or coefficients to five decimal places.)

Atoms containing radioactive nuclei are called

You want to move a heavy box with mass 30.0 kg across a carpeted floor. you pull hard on one of the edges of the box at an angle 30∘ above the horizontal with a force of magnitude 240 n, causing the box to move horizontally. the force of friction between the moving box and the floor has magnitude 41.5 n . what is the box's acceleration just after it begins to move