An electric kettle consumes `1 kW` of electric power when operated at `220 V`. A fuse-wire of what rating must be used for it ?

Options

A. `1 A`
B. `2 A`
C. `4 A`
D. `5 A`

Explanation

To determine the appropriate fuse wire rating for the electric kettle that consumes 1 kW of power when operated at 220 V, we can follow these steps:

### Step 1: Convert Power to SI Units
The power given is in kilowatts (kW), and we need to convert it to watts (W).
\[ 1 \text{ kW} = 1000 \text{ W} \]

### Step 2: Use the Power Formula
We know the relationship between power (P), voltage (V), and current (I) is given by the formula:
\[ P = V \times I \]
Where:
- \( P \) is the power in watts,
- \( V \) is the voltage in volts,
- \( I \) is the current in amperes.

### Step 3: Rearranging the Formula to Find Current
We can rearrange the formula to solve for current (I):
\[ I = \frac{P}{V} \]

### Step 4: Substitute the Values
Now, we can substitute the values of power and voltage into the formula:
\[ I = \frac{1000 \text{ W}}{220 \text{ V}} \]

### Step 5: Calculate the Current
Calculating the above expression:
\[ I = \frac{1000}{220} \approx 4.54 \text{ A} \]

### Step 6: Determine the Fuse Rating
The current calculated is approximately 4.54 A. A fuse must be rated higher than the maximum current to prevent it from blowing during normal operation. Therefore, we should choose a fuse rating that is higher than 4.54 A.

### Step 7: Select the Appropriate Fuse Rating
Among the given options (1 A, 2 A, 4 A, 5 A), the most appropriate fuse rating that is higher than 4.54 A is:
\[ \text{5 A} \]

Thus, the rating of the fuse wire that must be used for the electric kettle is **5 A**.

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