Enquanto se expande, um gás recebe o calor Q = 100J e realiza o trabalho W = 70J. Ao final do
processo, podemos afirmar que a energia interna do
gás
a) aumentou 170 J. b) aumentou 100 J.
c) aumentou 30 J. d) diminuiu 70 J.
e) diminuiu 30 J.

Along wire carrying a 4.2 a current perpendicular to the xy-plane intersects the x-axis at x=−1.7cm. a second, parallel wire carrying a 3.0 a current intersects the x-axis at x=+1.7cm. part a at what point on the x-axis is the magnetic field zero if the two currents are in the same direction? express your answer to two significant figures and include the appropriate units.