Simple Query on Option writing

Dear all
Please clarify my simple query regarding option writing.
Please consider the following eg:
I feel that the market is trending upwards and hence I do the below trade for April-16 expiry
Sell one Nifty PE 7750 at 50 with spot Nifty at approx 7850.

Please correct me if the below mentioned assumption is right:
In theory when I write a put option at 7750 I am not expecting the nifty to drop to below 7750.At the same time if the nifty trades above 7750 during expiry I get to keep the premium of 50 (X no of units).
Hence in theory my loss is unlimited but profits are limited to the premium amount.

However theory is much different from practical and hence my question is what happens to my investment in following scenarios

1. What happens to my trade if Nifty closes at 7700
2. What happens to my trade if Nifty closes at 7750
3. What happens to my trade if Nifty closes at 7800
4. In case of a wild swing say downwards to 7500 or upwards to 8200

Awaiting your kind consideration

:thanx: Rosh

Upon expiration, there can be 2 possible scenarios for the Naked Put Write :

1. The underlying stock rises higher than the strike price
When the underlying stock is trading higher than the strike price of the put options that you sold upon expiration, those put options expires out of the money (OTM) and the entire price of the put options that you sold becomes your profit.

2. The underlying stock is trading lower than the strike price

Loss = Net Credit - (Strike Price - Stock Price) x Number of Contracts.

_________________________________

Maximum Loss of Naked Put Write:
Maximum loss = (Strike Price - Premium Value) x Number of Contracts.

Break Even Point of Naked Put Write:
Breakeven = Strike price - premium value of put options sold

So in your case if we take 1 lot.

Anything above 7750 you get to keep the premium = 50 * 75 = 3,750.

Anything less than 7750 [suppose 7500] will be = 3,750 - (7750 - 7500) * 75

= Loss of Rs. 15,000.

If it closes at 7750 then = 3750 - (7750-7750) * 75

therefore premium is yours.

Thanks Leonid.
I have a few queries regarding a Call buy and Put sell vice versa.I will try to understand practically first what you have explained and if I dont get an an answer will post again.
Till then thanks once again