What is the change in entropy of helium gas with total mass 0.120 kg at the normal boiling point of helium when it all condenses isothermally to liquid helium? assume that the normal boiling point of helium is 4.216 k and the heat of vaporization of helium is 2.09×10^4 j/kg .

(2) (a) you have a simple circuit that consists of only a battery (δvbat=1.5v) and two resistors with resistance r1=10ω and r2=5ω, connected in series with each other. what is the current running through the battery? (b) you re-arrange your circuit so now r2 is attached in parallel to r1 rather than in series. what is the current running through the battery? (c) you add an additional resistor r3=7ω on the same branch as r2. what is the current running through the battery? (d) what is the power dissipated in r3?