Question

What is the potential difference across the source?
60 V
220 V
440 V
120 V

Answer 1

Answer:

120 v

Explanation:

The two resistors have an equivalent of    20 * 30 /(20+30) = 12 ohms

  10 amps of current in the circuit

v = ir

  = 10 * 12 = 120 volts

Here is another way:

The two resistors are in prallel so the voltae across both is the same

  use the one on the right      v = ir     =   4 x 30 = 120 v