Thanks for your information... But I mean to say that the Physical Size of the 1tb Hard Disk can sit into the 500 GB hard Disk Slot...
However, verify the thickness (height) and other dimensions of the 1 TB drive. You can do this by downloading and running SPECCY - http://www.piriform.com/speccy
From this you can obtain the hard disk details and model and serial number. Then go to the manufacturer's website and read the specifications which will list the physical dimensions.
Another way to do this is to take the disk out and take it to a computer store like MicroCenter and verify the physical dimensions. In most instances, a thicker hard disk such as the 1 TB hard disk will fit.
When changing from a 500 GB to a 1 TB hard disk, the thermal profile will be altered. If the heat produced is equal or less than the old 500 GB then it will be ok. If not, there may be new heat related problems created in a laptop.