Questions from College Physics

Q: A large room in a house holds 975 kg of dry air

A large room in a house holds 975 kg of dry air at 30.0°C. A woman opens a window briefly and a cool breeze brings in an additional 50.0 kg of dry air at 18.0°C. At what temperature will the two air m...

Q: A wire 50.0 m long and 2.00 mm

A wire 50.0 m long and 2.00 mm in diameter is connected to a source with a potential difference of 9.11 V, and the current is found to be 36.0 A. Assume a temperature of 20°C and, using Tab...

Q: A copper wire has a circular cross section with a radius of

A copper wire has a circular cross section with a radius of 1.25 mm. (a) If the wire carries a current of 3.70 A, find the drift speed of electrons in the wire. (Take the density of mobile charge carr...

Q: A rectangular block of copper has sides of length 10. cm

A rectangular block of copper has sides of length 10. cm, 20. cm, and 40. cm. If the block is connected to a 6.0 - V source across two of its opposite faces, what are (a) The maximum current and (b) T...

Q: The resistivity of copper is 1.70 x 10-8

The resistivity of copper is 1.70 x 10-8 Ω · m. (a) Find the resistance of a copper wire with a radius of 1.29 mm and a length of 1.00 m. (b) Calculate the volume of copper in the wire. (c) Suppose th...

Q: The human body can exhibit a wide range of resistances to current

The human body can exhibit a wide range of resistances to current depending on the path of the current, contact area, and sweatiness of the skin. Suppose the resistance across the chest from the left...

Q: Starting from Ohm’s law, show that E = Jρ, where

Starting from Ohm’s law, show that E = Jρ, where E is the magnitude of the electric field (assumed constant) and J = I/A is called the current density. The result is in fact true in general.

Q: If a certain silver wire has a resistance of 6.00

If a certain silver wire has a resistance of 6.00 Ω at 20.0°C, what resistance will it have at 34.0°C?

Q: Digital thermometers often make use of thermistors, a type of resistor

Digital thermometers often make use of thermistors, a type of resistor with resistance that varies with temperature more than standard resistors. Find the temperature coefficient of resistivity for a...

Q: A length of aluminum wire has a resistance of 30.0

A length of aluminum wire has a resistance of 30.0 Ω at 20.0°C. When the wire is warmed in an oven and reaches thermal equilibrium, the resistance of the wire increases to 46.2 Ω. (a) Neglecting therm...