Which of the following statement regarding heat transfer through stationary fluid is correct? select one: a. conduction occurs when temperature gradient exists in stationary fluid ο b. convection occurs when temperature gradient exists in stationary fluid ο c. radiation occurs when temperature gradient exists in stationary fluid d. no heat transfer occurs when temperature gradient exists in stationary fluid

b. Convection occurs when temperature gradient exist in stationary fluid.

Explanation:

Convection : heat transport through fluid movement;  It also occur when there is heat exchange between a solid and a fluid.  

there are two types:

                  Q = h * A * ΔT

∴ h : film coeffcient

The uncharged water is attracted to the charged balloon.

Explanation:

Electrostatics is the study of charges at rest. Neutral bodies have equal and evenly distributed positive and negative charges. However, these neutral bodies can become either positively or negatively charged. These charges can be produced by either of friction, contact or electrostatic induction.

For example, when an ebonite rod is rubbed with fur, the ebonite rod acquires a charge by friction. The ebonite rod becomes negatively charged while the fur is left with positive charges.

Similarly, for the experiment performed by Yolanda, when she rubs a cloth against a balloon, the balloon becomes negatively charged . Water is neutral in that it is composed of equal positive and negative charged particles. When she brings the balloon near the water, the positive charged particles in the water will move the water towards the negatively charged balloon since positive and negative charges are attracted to each other.