unable to download application in my iphone

Hello dr.c.s.s.vinod,

Thank you for the details of the issue you are experiencing with the App Store on your iPhone. I found an article with steps I recommend for the issue you described. The article title refers to the iTunes Store, but the steps are relevant for the App Store as well.

Troubleshoot issues on an iPhone, iPad, or iPod touch

If you haven't been able to connect to the iTunes Store:

• Make sure your date, time, and time zone are correct in Settings > General > Date & Time.
  Note: Time Zone may list another city in your time zone.
• Make sure that your iOS software is up to date by tapping Settings > General > Software Update (iOS 5 or later) or connecting your iOS device to iTunes and clickingCheck for Updateon your device's Summary page.
• Check and verify that you're in range of a Wi-Fi router or base station. If you're on a device with cellular service, make sure that cellular data is turned on from Settings > General > Cellular.
  Note: If connected to cellular data, larger items may not download. You may need to connect to Wi-Fi to download apps, videos, and podcasts.
• Make sure that you have an active Internet connection. You can check the user guide for your device for help with connecting to the Internet.
• Make sure that other devices (portable computers, for example) are able to connect to the Wi-Fi network and access the Internet.
• Try resetting (turning off and then on again) your Wi-Fi router.
• If the issue persists, try troubleshooting your Wi-Fi networks and connections.

Can't connect to the iTunes Store

http://support.apple.com/kb/ts1368

Thank you for using Apple Support Communities.

Best,

Sheila M.