Question

Which of the following signs on q and w represent a system that is doing work on the surroundings, as well as losing heat to the surroundings?
A) q = - , w = -
B) q = +, w = +
C) q = -, w = +
D) q = +, w = -
E) None of these represent the system referenced above.

Answer 1

Answer:

A

Explanation:

Work (w) is categorized by net, in as positive work done on the system,hence, Work done by the system is negative

Heat transfer (q) is categorized by net, in as positive Heat transfer in to the system,hence, Heat loss from the system is negative.

Answer: q = - , w = -

Answer 2

Answer:c

Explanation:

In Physics we follow the sign convention i.e. work done by the system is considered as positive i.e. work is being done by system on the surrounding and vice-versa.

For heat :Heat added to the system is considered as Positive while heat loss to surrounding is considered as negative.

thus doing work on the surrounding(work done by system) w=+

Losing heat to the surrounding q=-