Physics for Scientists and Engineers, 6e Chapter 24 – Gauss’s Law

Suppose the radius of the sphere in Example 24.1 (radius 1.00 m, with a charge of μC at its center) is changed to m. What happens to the flux through the sphere and the magnitude of the electric field at the surface of the sphere? The flux and field both increase. 2.The flux and field both decrease. 3.The flux increases and the field decreases. 4.The flux decreases and the field increases. 5.The flux remains the same and the field increases. 6.The flux decreases and the field remains the same.

The same number of field lines pass through a sphere of any size. Because points on the surface of the sphere are closer to the charge, the field is stronger.

In a charge-free region of space, a closed container is placed in an electric field. A requirement for the total electric flux through the surface of the container to be zero is that the field must be uniform 2.the container must be symmetric 3.the container must be oriented in a certain way 4.The requirement does not exist – the total electric flux is zero no matter what.

All field lines that enter the container also leave the container so that the total flux is zero, regardless of the nature of the field or the container.

Consider the charge distribution shown in the figure. The charges contributing to the total electric flux through surface S’ are q 1 only 2. q 4 only 3. q 2 and q 3 4. all four charges 5. none of the charges

The charges q 1 and q 4 are outside the surface and contribute zero net flux through S’.

Again consider the charge distribution shown in this figure. The charges contributing to the total electric field at a chosen point on the surface S’ are q 1 only 2. q 4 only 3. q 2 and q 3 4. all four charges 5. none of the charges

We don't need the surfaces to realize that any given point in space will experience an electric field due to all local source charges.

Your little brother likes to rub his feet on the carpet and then touch you to give you a shock. While you are trying to escape the shock treatment, you discover a hollow metal cylinder in your basement, large enough to climb inside. In which of the following cases will you not be shocked? You climb inside the cylinder, making contact with the inner surface, and your charged brother touches the outer metal surface. 2.Your charged brother is inside touching the inner metal surface and you are outside, touching the outer metal surface. 3.Both of you are outside the cylinder, touching its outer metal surface but not touching each other directly.

Charges added to the metal cylinder by your brother will reside on the outer surface of the conducting cylinder. If you are on the inside, these charges cannot transfer to you from the inner surface. For this same reason, you are safe in a metal automobile during a lightning storm.