Correct Answer - Option 4 : 75 degree W. Longitude
The correct answer is 75 degrees W. Longitude.
Finding Direction:
\(\implies \)Current time in India = 12:00 p.m.
\(\implies \)Time at required meridian = 7:00 a.m.
\(\implies \)Difference in time = 5 hrs, and this time at meridian(7:00 a.m.) is 5 hrs behind. Hence it is west direction.
Note: When time on a meridian is lagging with respect to the time of others, then it lies to the west.
Calculation of Longitude:
As we know the Earth takes 24 hrs. for one complete rotation, so
\(\implies \)24 hrs. = 360°
\(\implies \)1 hr = \(\frac {360} {24}\)= 15°, thus the Earth rotates 15 degrees in 1 hr.
\(\implies \)In 5 hrs = 5 × 15° = 75°.
Hence at 75° West longitude, the time will be 7:00 a.m.