Question

he will come back in -----------hour
​

Answer 1

Answer:

He will come back in an hour

Answer 2

$\sf{Answer:-}$

He will come back in an hour.

The Article "an" is used before the word "hour". This is because of the silent h in hour.

The silent h makes the word hour pronounced as our.

According to the fact, We use "an" before vowel sounds.

Hence, the answer is an.