Three simple queries

Dear Readers and Experts,
i am having little knowledge in trading, can some clarify following queries

My queries
what is total time for full candle stick formation 3 min or 5 min any else?

with respect market, 1 day = 24 hrs or 1 day = (how many hours)?

For hourly (say 20 hr EMA) EMA calculation how much days should i consider is it around 1 day or 3 days (as per 6 hours market)

Candlestick formation - Each candle represents the price action in the time period of the chart that you have chosen. So, if you are looking at a 5-min chart, each candle represents the open/low/high/close prices in that 5 minutes.

1 day = Meaning of a day differs according to markets. For forex markets, 1 day = 24 hours. for equities, 1 day = 6 hours or 8 hours or 9 hours or x hours (depending upon the exchange).

If you want a 20 period EMA in a chart, then you need to have a minimum of 20 periods covered by the chart data. My opinion is that you should have at least twice the minimum number of periods to indicate you the direction of the EMA. So, for a 20 period EMA, I would recommend having data for at least 40 periods.
Going by this, you need 40 hours of data for a 20 period EMA on a hourly chart. This mean you would need 7 days data (assuming 6 hours per day).