Question

If the time on Greenwich Meridian is 10.00 am, the time on $66^\circ$ east longitude is

• A. 5.36 am
• B. 2.24 pm
• C. 4.24 pm
• D. 5.24 am

Hint:

For every $1^\circ$ of longitude, the time changes by 4 minutes. If moving east, add the time difference; if moving west, subtract it.

Answer 1

The Correct Option is B

Step 1: Determine the time difference per degree of longitude.
The Earth completes one full rotation ($360^\circ$) in 24 hours.
Therefore, for every $1^\circ$ of longitude, the time difference is: \[ \frac{24 \text{ hours}}{360^\circ} = \frac{1}{15} \text{ hours/degree} \] Convert this to minutes: \[ \frac{1}{15} \text{ hours/degree} \times 60 \text{ minutes/hour} = 4 \text{ minutes/degree}. \]

Step 2: Calculate the total time difference for $66^\circ$ East longitude.
For $66^\circ$ East longitude, the time will be ahead of the Greenwich Mean Time (GMT) because it is to the east.
Total time difference = $66^\circ \times 4 \text{ minutes/degree} = 264 \text{ minutes}$.

Step 3: Convert the time difference to hours and minutes.
264 minutes = $\frac{264}{60}$ hours = 4 hours and 24 minutes.

Step 4: Calculate the time at $66^\circ$ East longitude.
Given time at Greenwich Meridian (GMT) = 10:00 am.
Time at $66^\circ$ East longitude = 10:00 am + 4 hours 24 minutes Time at $66^\circ$ East longitude = 2:24 pm.