Before the advent of solid-state electronics, vacuum tubes were widely used in radios and other devices. A simple type of vacuum tube, known as a diode, consists of two cylindrical electrodes within a highly evacuated enclosure. One electrode, the cathode, is maintained at a high temperature and emits thermally excited electrons from its surface. The other electrode, called the anode, is maintained at a certain voltage above the cathode, so the ejected electrons accelerate toward the anode. Suppose the cathode has a radius of 0.620 mm, and that the coaxial cathode has a radius of 55.8mm. The potential difference between the anode and cathode is 370 V. If an electron leaves the cathode at rest, what will be its speed when it reaches the andoe?

The step-down transformer gives a current of 10a at 24v if the primary voltage is 240v calculate the 1_primary current 2_the power input 3_the power output

Under conditions for which the same room temperature is maintained by a heating or cooling system, it is not uncommon for a person to feel chilled in the winter but comfortable in the summer. provide a plausible explanation for this situation (with supporting calculations) by considering a room whose air temperature is maintained at 20â°c throughout the year, while the walls of the room are nominally at 27â°c and 14â°c in the summer and winter, respectively. the exposed surface of a person in the room may be assumed to be at a temperature of 32â°c throughout the year and to have an emissivity of 0.90. the coefficient associated with heat transfer by natural convection between the person and the room air is approximately 2 w/m2 â‹…â‹… k. what is the ratio of the thermal resistance due to convection to the thermal resistance due to radiation in the summer? what is the ratio of thermal resistances in the winter

The velocity of car is 80.0 miles per hour. what is the velocity of car in meters per second? (1 km -0.621 miles) m/s