A resistor R and a `4muF` capacitor are connected in series across a 200 V d.c. supply. Across the capacitor is connected a neon lamp that strikes at 120 V in 5 seconds . Find R.

Explanation

To solve the problem step by step, we will follow the logical flow of the equations and concepts involved in the charging of a capacitor in an RC circuit.

### Step-by-Step Solution:

1. **Understand the Circuit Configuration**:
- We have a resistor \( R \) and a capacitor \( C = 4 \mu F \) connected in series across a DC supply of \( V = 200 V \).
- A neon lamp is connected across the capacitor, which strikes at a voltage of \( V_{lamp} = 120 V \) after \( t = 5 \) seconds.

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