What does a switch in an electrical circuit do? O A. It concentrates negative charges on one side of the circuit when it
is open.
B. It concentrates negative charges on one side of the circuit when it
is closed.
C. It allows electrons to flow from one part of the circuit to another
when it is open.
D. It allows electrons to flow from one part of the circuit to another
when it is closed.

Na food processing facility, a spherical container of inner radius r1 5 40 cm, outer radius r2 5 41 cm, and ther- mal conductivity k 5 1.5 w/m · k is used to store hot water and to keep it at 100°c at all times. to accomplish this, the outer surface of the container is wrapped with a 800-w electric strip heater and then insulated. the temperature of the inner surface of the container is observed to be nearly 120°c at all times. as- suming 10 percent of the heat generated in the heater is lost through the insulation, (a) express the differential equation and the boundary conditions for steady one-dimensional heat conduction through the container, (b) obtain a relation for the variation of temperature in the container material by solving the differential equation, and (c) evaluate the outer surface tempera- ture of the container. also determine how much water at 100°c this tank can supply steadily if the cold water enters at 20°c.

Which accurately compares concave and convex lenses?

In automobile steering wheel is shown what is the ideal mechanical advantage blank? if the ama is eight what is the efficiency of the steering wheel?