One watt-hour is equivalent to A. 6.3 x 103 J B. 6.3 x 10-7 J C. 3.6 x 103 J D. 3.6 x 10-3 J

6.3 x 103 J
6.3 x 10-7 J
3.6 x 103 J
3.6 x 10-3 J

The correct answer is C. 3.6 x 103 J.

One watt-hour is equivalent to 3.6 x 103 J because 1 watt is equal to 1 joule per second, and 1 hour is equal to 3600 seconds. Therefore, 1 watt-hour is equal to 1 joule per second x 3600 seconds = 3.6 x 103 J.

Option A is incorrect because 6.3 x 103 J is equal to 6.3 kilojoules, which is not equal to one watt-hour.

Option B is incorrect because 6.3 x 10-7 J is equal to 6.3 microjoules, which is also not equal to one watt-hour.

Option D is incorrect because 3.6 x 10-3 J is equal to 3.6 millijoules, which is also not equal to one watt-hour.