When a metal is heated its density decreases. there are two sources that give rise to this decrease of rho: (1) the thermal expansion of the solid and (2) the formation of vacancies (section 5.2). consider a specimen of gold at room temperature (20°c) that has a density of 19.320 g/cm3 . (a) determine its density upon heating to 800°c when only thermal expansion is considered. (b) repeat the calculation when the introduction of vacancies is taken into account. assume that the energy of vacancy formation is 0.98 ev/atom, and that the volume coefficient of thermal expansion, αv is equal to 3αl .

Astudent looks at ocean waves coming into the beach. an ocean wave with more energy will a) have a greater height. b) have a greater period. c) travel toward the beach faster. d) strike the beach with greater frequency.

Which statement correctly describes the current in a circuit that is made up of any two resistors connected in parallel with a battery? a. the current in the battery and in each resistor is the same b. the current the battery equals to the sum of the currents in the resistors c.the current in the battery is less than the current in either resistor d. the current in the battery equals to the product of the currents in the resistors

Imagine an isolated positive point charge q (many times larger than the charge on a single proton). there is a charged particle a (whose charge is much smaller than charge q) at a distance from the point charge q. on which of the following quantities does the magnitude of the electric field created by charge q at particle a's position depend? check all that apply.the type of the charge on the charged particle athe relative orientation between q and a (while the distance between q and a is fixed)the specific location of the charged particle a (while the distance between q and a is fixed)the amount of the charge on the point charge qthe specific location of the point charge q (while the distance between q and a is fixed)the distance between the point charge q and the charged particle athe amount of the charge on the charged particle a