An electric bulb of 100 W is used for 9 hours per day. What will be the units of energy consumed in 1 day by the bulb?

Options

A. 0.9 units
B. 0.6 units
C. 1.2 units
D. 1.9 units

Answer

To find the energy consumed by a 100 W electric bulb used for 9 hours per day, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Power of the Bulb**:
- The power of the bulb is given as 100 W (watts).

2. **Convert Power to Kilowatts**:
- Since energy is often measured in kilowatt-hours (kWh), we convert watts to kilowatts:
\[ \text{Power in kilowatts} = \frac{100 \text{ W}}{1000} = 0.1 \text{ kW} \]

3. **Determine the Time of Usage**:
- The bulb is used for 9 hours per day.

4. **Use the Formula for Energy**:
- The formula to calculate energy consumed is:
\[ \text{Energy} = \text{Power} \times \text{Time} \]
- Substituting the values we have:
\[ \text{Energy} = 0.1 \text{ kW} \times 9 \text{ hours} = 0.9 \text{ kWh} \]

5. **Conclusion**:
- The energy consumed by the bulb in one day is 0.9 kWh, which is also referred to as 0.9 units of electricity.

### Final Answer:
The energy consumed in one day by the bulb is **0.9 units**.