Total amount of heat produced by a fuel having calorific value of 30 kJ/kg.was found to be 60,000 joules. How much fuel was burnt?

Options

A. 2000 kg
B. 200 kg
C. 20 kg
D. 2 kg

Answer

To solve the problem, we need to determine how much fuel was burnt based on the calorific value and the total heat produced. Here’s a step-by-step solution:

### Step 1: Understand the given values
- **Calorific value of the fuel** = 30 kJ/kg
- **Total heat produced** = 60,000 J

### Step 2: Convert the total heat produced from joules to kilojoules
Since the calorific value is given in kilojoules, we need to convert the total heat produced into kilojoules:
\[ \text{Total heat in kJ} = \frac{60,000 \text{ J}}{1000} = 60 \text{ kJ} \]

### Step 3: Use the calorific value to find the amount of fuel burnt
The calorific value tells us how much heat is produced by burning 1 kg of fuel. Therefore, if we burn \( x \) kg of fuel, the heat produced can be expressed as:
\[ \text{Heat produced} = \text{Calorific value} \times \text{Amount of fuel burnt} \]
This can be written as:
\[ 60 \text{ kJ} = 30 \text{ kJ/kg} \times x \text{ kg} \]

### Step 4: Solve for \( x \)
Rearranging the equation to solve for \( x \):
\[ x = \frac{60 \text{ kJ}}{30 \text{ kJ/kg}} = 2 \text{ kg} \]

### Conclusion
The amount of fuel burnt is **2 kg**.

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