A certain battery has terminals labeled a and b. The battery voltage is vab = 12 V. a) To increase the chemical energy stored in the battery by 900J, how much charge must move through the battery? b) Should electrons move from a to b or from b to a?

 a) To determine how much charge must move through the battery to increase its chemical energy by 900 J, we can use the relationship between voltage (V), charge (Q), and energy (W), which is given by the formula:

W = Q * V

Where: W is the energy in joules (J), Q is the charge in coulombs (C), and V is the potential difference in volts (V).

We're given: W = 900 J (the energy to increase) V = 12 V (the battery voltage)

We need to find Q, so we rearrange the formula to solve for Q:

Q = W / V

Plugging in the given values:

Q = 900 J / 12 V = 75 C

So, 75 coulombs of charge must move through the battery to increase its chemical energy by 900 J.

b) Electrons should move from the negative terminal to the positive terminal to increase the chemical energy of the battery. However, conventional current considers the direction of positive charge flow. Since the battery's terminals are labeled a and b and we have the voltage vab = 12 V, we infer that a is the positive terminal and b is the negative terminal. Thus, in terms of conventional current (positive charge flow), the charge must move from terminal b to terminal a to increase the battery's chemical energy.