Q: wifi connectivity is very weak  on iphone 5

Hi vishnuloya,

Thanks for using Apple Support Communities. Based on what you stated, it sounds like the iPhone is having trouble connecting to other networks. I would recommend that you read these articles, they may be helpful in troubleshooting your issue.

If your iPhone, iPad, or iPod touch won’t connect to a Wi-Fi network - Apple Support

Reset your Network Settings. Tap Settings > General > Reset > Reset Network Settings. This also resets Wi-Fi networks and passwords, cellular settings, and VPN and APN settings that you’ve used before.

iOS and OS X: Recommended settings for Wi-Fi routers and access points - Apple Support

Cheers,

Mario