### DC Circuits Problems

SAT Physics questions require knowledge of DC circuits, Ohm's law, resistors, capacitors, Kirchhoff's laws.

1. What is the capacitance between the points A and B if C_{1}= C

_{2}= C

_{3}= 10

^{-6}F?

a) 10

^{-6}F

b) 2·10

^{-6}F

c) .67·10

^{-6}F

d) .5·10

^{-6}F

e) 1.5·10

^{-6}F

2. A DC voltage source is connected to two resistors in series, as shown in the figure below. What is the ratio between the power dissipation of resistor R

_{1}and the power dissipation of resistor R

_{2}?

a) (R

_{1}/R

_{2})

^{2}

b) (R

_{2}/R

_{1})

^{2}

c) (1 - R

_{1})/(1 - R

_{2})

d) R

_{1}/R

_{2}

e) R

_{2}/R

_{1}

3. A copper wire of length l

_{1}= 6 m and cross-sectional area of A

_{1}= 4 mm

^{2}has the same resistance as a different copper wire of length l

_{2}= 18m. What is the ratio between the masses of the two wires, m

_{1}/m

_{2}?

a) 9

b) 3

c) 1

d) 1/9

e) 1/3