The voltage across a lamp is 6.82 V when the current passing through it is 4.1 A. Find the power consumed to appropriate significant figures.

Answer

To solve the problem of finding the power consumed by the lamp, we will follow these steps:

### Step 1: Identify the given values
We have the following values:
- Voltage (V) = 6.82 V
- Current (I) = 4.1 A

### Step 2: Use the formula for power
The formula to calculate power (P) is given by:
\[ P = V \times I \]
where P is the power in watts, V is the voltage in volts, and I is the current in amperes.

### Step 3: Substitute the values into the formula
Now, substituting the given values into the formula:
\[ P = 6.82 \, \text{V} \times 4.1 \, \text{A} \]

### Step 4: Perform the multiplication
Calculating the multiplication:
\[ P = 6.82 \times 4.1 = 27.962 \, \text{W} \]

### Step 5: Determine the significant figures
Next, we need to express the power in appropriate significant figures. The voltage (6.82 V) has 3 significant figures, while the current (4.1 A) has 2 significant figures. The result should be reported in the lesser number of significant figures, which is 2.

### Step 6: Round the result
The calculated power is 27.962 W. To round this to 2 significant figures:
- The first two digits are 27.
- The third digit is 9, which is greater than 5, so we round up.

Thus, rounding 27.962 to 2 significant figures gives us:
\[ P \approx 28 \, \text{W} \]

### Final Answer
The power consumed by the lamp is approximately **28 W**.

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