The effect of closing the key K in the circuit shown in the figure above would be to?
Attached Figure / Diagram
A
increase the current by 0.4A
B
reduce the current by 0.4A
C
increase the current by 0.6A
D
reduce the current by 0.6A
Verified Correct Answer: A.
Physical Principles & Numerical Solution
When K is open. Total Resistance = 8 + 2 = 10\(\Omega\)
1 = \(\frac{V}{\Omega}\) = \(\frac{6v}{\Omega}\) = 0.6A
Where K is closed, \(\frac{1}{8} + \frac{1}{8} = \frac{1}{\Omega}\)
\(\frac{2}{8} = \frac{1}{\Omega}\)
\(\Omega\) = \(\frac{8}{2}\) = 4\(\Omega\)
\(\Omega\) = \(\frac{8}{2}\) = 4\(\Omega\)
4\(\Omega\) in series with 2\(\Omega\)= 6\(\Omega\)
1 = \(\frac{V}{\Omega}\) = \(\frac{6}{6}\) = 1A
1 - 0.6A = 0.4A increase
Source: Myschool Past Questions Archive (Record #56897)