Three resistors of 3.3 kΩ, 4.7 kΩ and 3.9 kΩ are connected in series across a 12 V battery
a. What is the equivalent resistance?
b. What is the current through the resistors?
c. Find the total potential difference across the three resistors.

Explanation:

A.) equivalent resistance

Equivalent resistance ( Rt ) in a series connection is sum of all resistance.

Rt = 3300 + 4700 + 3900

= 11900 ohms

= 11.9 k ohm

B.) current is constant across the whole circuit if it is in series .

current = potential difference ÷ total resistance

current = 12 / 11900 = 0.00100 Amphere

= 0.1 mA

C. potential difference ( v ) across the circuit =

current( i ) × resistance ( Rt )

=》v = 0.1 × 0.001 × 11900 = 12 volts