Can I connect a external hard drive with usb 3.0 with my lenovo b460e which has usb 2.0 port?

[Ram madesh]

I bought a Sony external hard drive with 1tb and connected to my lenovo b460e laptop. But the device is not showing. Why?

 

[webworkings]

Well if the computer only has a USB 2.0 port and the device you are trying to connect is a USB 3.0 device, then it won't connect properly. While you can use a 3.0 port to connect a 2.0 device, the reverse doesn't work. You would either need to use a 3.0 port (if your device has one) or get yourself an external drive that uses 2.0.