Shrinath switched on a bulb at `1 : 44 : 41` hours and switched it off on the same day at `11 : 35 : 35` hours . For how many long was the bulb in switched-on mode ?

Options

A. 9 hours 50 minutes 54 seconds
B. 9 hours 09 minutes 06 seconds
C. 10 hours 09 minutes 06 seconds
D. 12 hours 40 minutes 06 seconds

Answer

To find out how long the bulb was switched on, we need to calculate the difference between the time it was switched on and the time it was switched off.

### Step-by-Step Solution:

1. **Identify the Switch-On and Switch-Off Times:**
- Switch-On Time: `1:44:41` (1 hour, 44 minutes, and 41 seconds)
- Switch-Off Time: `11:35:35` (11 hours, 35 minutes, and 35 seconds)

2. **Convert Both Times to Seconds:**
- For the Switch-On Time:
- Hours to seconds: \(1 \times 3600 = 3600\) seconds
- Minutes to seconds: \(44 \times 60 = 2640\) seconds
- Seconds: \(41\) seconds
- Total Switch-On Time in seconds:
\[ 3600 + 2640 + 41 = 6281 \text{ seconds} \]

- For the Switch-Off Time:
- Hours to seconds: \(11 \times 3600 = 39600\) seconds
- Minutes to seconds: \(35 \times 60 = 2100\) seconds
- Seconds: \(35\) seconds
- Total Switch-Off Time in seconds:
\[ 39600 + 2100 + 35 = 41735 \text{ seconds} \]

3. **Calculate the Duration the Bulb was On:**
- Duration in seconds:
\[ 41735 - 6281 = 35454 \text{ seconds} \]

4. **Convert the Duration Back to Hours, Minutes, and Seconds:**
- Calculate hours:
\[ 35454 \div 3600 = 9 \text{ hours} \quad (\text{remainder } 35454 - 9 \times 3600 = 54) \]
- Calculate minutes:
\[ 54 \div 60 = 0 \text{ minutes} \quad (\text{remainder } 54 - 0 \times 60 = 54) \]
- Remaining seconds: \(54\) seconds

5. **Final Result:**
- The bulb was switched on for **9 hours, 50 minutes, and 54 seconds**.

### Summary:
The total time the bulb was in the switched-on mode is **9 hours, 50 minutes, and 54 seconds**.