The nutrients value of sweet is 360 kcal. The energy from it will be sufficient to light a bulb of 100W for how much time?

Options

A. 1h
B. 2h
C. 4h and 12min
D. 4h and 2 min

Explanation

To solve the problem of how long a 100W bulb can be lit using the energy from a sweet with a nutrient value of 360 kcal, we can follow these steps:

### Step 1: Convert kcal to Joules
The first step is to convert the energy from kilocalories (kcal) to joules (J). We know that:
1 kcal = 4.2 kJ = 4200 J.

So, for 360 kcal:
\[ \text{Energy in Joules} = 360 \, \text{kcal} \times 4200 \, \text{J/kcal} = 1512000 \, \text{J} \]

### Step 2: Understand the power of the bulb
The power of the bulb is given as 100W. Since 1 Watt is equivalent to 1 Joule per second, we can express the power in joules:
\[ \text{Power} = 100 \, \text{W} = 100 \, \text{J/s} \]

### Step 3: Use the formula for energy
The relationship between energy, power, and time can be expressed as:
\[ \text{Energy} = \text{Power} \times \text{Time} \]
Rearranging this formula to find time gives us:
\[ \text{Time} = \frac{\text{Energy}}{\text{Power}} \]

### Step 4: Substitute the values
Now, we can substitute the values we have into the formula:
\[ \text{Time} = \frac{1512000 \, \text{J}}{100 \, \text{J/s}} = 15120 \, \text{s} \]

### Step 5: Convert seconds to hours and minutes
To convert seconds into hours and minutes:
1. Convert seconds to hours:
\[ \text{Hours} = \frac{15120 \, \text{s}}{3600 \, \text{s/h}} = 4.2 \, \text{hours} \]
2. To find the minutes, take the decimal part (0.2 hours) and convert it to minutes:
\[ 0.2 \, \text{hours} \times 60 \, \text{minutes/hour} = 12 \, \text{minutes} \]

Thus, the total time the bulb can be lit is **4 hours and 12 minutes**.

### Final Answer
The energy from the sweet will be sufficient to light a 100W bulb for **4 hours and 12 minutes**.

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