Apple Inc likely will dazzle investors with another round of strong quarterly results on Tuesday, propelled by demand for its iPhone and the new iPad 2 tablets.

But it's the second half of 2011 that is getting investors really excited -- that is when Apple's new iPhone likely will hit the market. Expectations that the company will beat analysts' fiscal third-quarter forecasts drove shares to a record high of $378.65 on Tuesday.

Shares of the world's most valuable technology company have emerged from the limbo they were in since Chief Executive Steve Jobs took leave last January for unspecified medical reasons. The stock price has gained nearly 19 percent since hitting a year low on June 20. The rally has added $54.8 billion to Apple's market cap since then.

The options market is implying a 2 percent earnings move up or down for the stock. JPMorgan Securities on Monday recommended buying Apple's August $365 call options ahead of the company's quarterly earnings.

Investors are looking for a 60 percent increase in revenue for the third quarter, which ended on June 25. Meanwhile, Wall Street is betting that the second half of the year will be huge because it may include the debut of a new iPhone, the best-selling product that accounts for about 40 percent of its revenue.

We are more positive on the outlook for share acceleration in the second half as it is reasonable to expect multiple hardware refreshes combined with the back-to-school and holiday shopping quarter, said BGC analyst Collin Gillis, who raised his price target on the stock to $430 from $390.

Apple is conservative with its forecasts. Investors will pick apart executives' comments to figure out how much the new iPhone will boost revenue.

Apple likely sold 17 million to 18 million iPhones during the quarter and about 8 million iPads, according to analysts, who expect lower component prices to boost gross margins to as high as 41 percent.

Apple is expected to report a profit of $5.85 a share on revenue of $24.9 billion, according to Thomson Reuters I/B/E/S. Apple has beaten Street estimates for 13 quarters in a row.

According to StarMine's SmartEstimate, which places more weight on recent forecasts by top-rated analysts, Apple should post EPS of $6.055 on revenue of $25.3 billion.

(Editing by Richard Chang and Robert MacMillan)