Two conductors A and B resistance `5 omega and 10 omega` respectively are first joined in parallel and then in series. In each case the voltage applied is 20 V.
Equivalent resistance in series combination is:

Options

A. `15 omega`
B. `3.33 omega`
C. `0.3 omega`
D. None of the above

Explanation

To find the equivalent resistance when two conductors A and B with resistances of 5 ohms and 10 ohms are connected in series, we can follow these steps:

### Step 1: Identify the resistances
We have:
- Resistance of conductor A, \( R_A = 5 \, \Omega \)
- Resistance of conductor B, \( R_B = 10 \, \Omega \)

### Step 2: Use the formula for equivalent resistance in series
When resistors are connected in series, the total or equivalent resistance \( R_s \) is given by the formula:
\[ R_s = R_A + R_B \]

### Step 3: Substitute the values into the formula
Now, substituting the values of \( R_A \) and \( R_B \) into the formula:
\[ R_s = 5 \, \Omega + 10 \, \Omega \]

### Step 4: Calculate the equivalent resistance
Now, perform the addition:
\[ R_s = 15 \, \Omega \]

### Conclusion
The equivalent resistance when the two conductors are connected in series is \( 15 \, \Omega \).

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