An electric bulb is rated as 55 W for 110 volt DC supply . It is connected across an AC source and its brightness is found to be normal . Calculate peak voltage of AC supply .

Explanation

To solve the problem step by step, we will follow the reasoning provided in the video transcript.

### Step 1: Understand the Relationship Between AC and DC
The electric bulb is rated at 55 W for a 110 V DC supply. When connected to an AC source, the brightness remains the same, which implies that the effective (RMS) voltage of the AC supply must be equal to the DC voltage of 110 V.

**Hint:** Remember that the brightness of a bulb depends on the power it receives, which is related to the voltage applied.

### Step 2: Identify the RMS Voltage
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