What do we mean by the event horizon of a black hole?
a) it is the place where x rays are emitted from black holes. b) it is the very center of the black hole. c) it is the point beyond which neither light nor anything else can escape. d) it is the distance from the black hole at which stable orbits are possible.

Jackson is designing a new heater, and he wants to experiment with different thermally conductive materials. which of these materials would be useful in conducting heat?

Examples of states of consciousness include a. daydreaming b. dreaming during sleep c. hypnosis d. all of the above

An air standard cycle with variable specific heats is executed in a closed system and is composed of the following four processes. 1-2 isentropic compression 100 kpa and 22°c to 600 kpa 2-3 v=constant heat addition to 1500 k 3-4 isentropic expansion to 100 kpa 4-1 p=constant heat rejection to initial state (a) show the cycle on p-v and t-s s (b) calculate the net work output per unit mass (409 kj/kg) (c) determine the thermal efficiency (47.9%)