Acarbon resistor is 4 mm long and has a constant cross section of 0.5 mm2. the conductivity of carbon at room temperature is 3 × 104 per ohm·m. in a circuit its potential at one end of the resistor is 11 volts relative to ground, and at the other end the potential is 14 volts. calculate the resistance and the current .

Which is not a characteristic of a heat pump? a. it is used in air conditioners. b. it uses a refrigerant. c. it requires no work. d. it reverses the normal flow of thermal energy.

What was the first instrument to ever record an earthquake?

When can a theory be modified if a new type of technology allows for new observations that raise new questions? a-immediately, while the questions about the theory are being asked b-after new hypotheses related to the theory are tested in experiments c-only after the new observations disprove all parts of the theory d-while scientists begin to think about how the theory could improve