Four students measure the mass of an object, each using a different scale. They record their results as follows: A: 49.06g, B: 49g, C: 50g, D: 49.2g. Which student used the least and most precise scale?

Ahuge (essentially infinite) horizontal nonconducting sheet 10.0 cm thick has charge uniformly spread over both faces. the upper face carries +95.0 nc/m2 while the lower face carries -25.0 nc/ m2. what is the magnitude of the electric field at a point within the sheet 2.00 cm below the upper face? (ε0 = 8.85 × 10-12 c2/n · m2)