Thanks immensely guys. I really appreciate. But my query is this, how then do I get a hash I'd that shows the exact amount I sent?
My advice would be to click on the "BTC" button and leave it there... stop dealing in "USD" and trying to send "exact USD" amounts... it is an "impossible" task as the USD price of BTC is literally changing every second (depending on the source you use).
If someone says "I want $10" and you're going to send them BTC, then you will need to agree on a set BTC-USD conversion rate (and/or a set price in BTC)... otherwise send them USD $10 via paypal or some other fiat currency transfer.
It's the same with fiat transfers... if someone says "I want USD$10" and instead you send them EUR€8.22 and in the meantime the conversion rate goes to 0.83... you've only sent them "USD$9.90"...