Cloning two operating systems partitions to new second hard diskl

Partha, what version of Acronis True Image do you have to use here?

Also, what BIOS mode do your 2 copies of Windows OS use? 
Is this a Legacy BIOS setup, or do you have UEFI BIOS?

Making some assumptions about the above questions, i.e. that your system is Legacy with MBR partitioning for the current 500GB HDD, and that your version of ATI is supported for use with Windows 10...

The approach that I would recommend would be as follows:

1. Run the Windows command: msinfo32 and confirm the BIOS mode used by both versions of Windows 10, that this is the same for both?
2. Boot into the primary Windows 10 OS and perform a full Disk & Partitions backup of the 500GB HDD drive, ensuring that all hidden/system partitions are included.
3. Create the Acronis bootable Rescue Media for your version of ATI and test that you can boot your computer using this, including seeing both the internal 500GB HDD and the external backup drive used in step 2. above.
4. Shutdown the computer and remove the 500GB HDD drive and replace this with your new 1TB HDD drive.  Leave the 500GB HDD out of the computer or disconnected at this time.
5. Boot the computer using the Acronis Rescue Media with the external backup drive connected.
6. Recover the full Disk & Partitions backup (made in step 2.) to the new 1TB HDD in disk mode (see forum topic: [How to] recover an entire disk backup for an example of how to do this.  Note: this was written for ATI 2017 but should be similar for earlier versions of the rescue media.
7. Shutdown, remove the external backup drive and Acronis Rescue Media and test that you can boot into Windows 10 for both of your dual-boot OS's from the new 1TB HDD.
8. If all the above is complete and successful, then shutdown, install the original 500GB HDD as a second drive in the computer, then format this ready for use as a data drive. Note: if you can connect the 500GB HDD via an USB adapter or dock, use this method to reformat the drive and remove the old Windows OS partitions.

Thank you very much for a very quick response.

BOOT MODE: Legacy BIOS in UEFI(Secure Boot not supported)For both os Was upgraded from Windows 7

My 1 tb seagate went kaput a few days ago so  I will find a external drive and come to you.thanks

ACRONIS TRUE IMAGE 2014

Partha, given your boot mode is Legacy, then you must ensure that the Acronis Rescue media is booted in the same Legacy mode when doing any recovery, as if you boot via UEFI, it will cause your MBR drive to be converted to GPT.

See KB 59877: Acronis True Image 2017: how to distinguish between UEFI and Legacy BIOS boot modes of Acronis Bootable Media

Yes sir and thanks

I have another  query.Suppose I retain new 1tb disk and discarding older one do I still need external drive for backing up

Partha, I would recommend still using an external drive for your backup and recovery especially as you are going to be changing drives and don't want to make any mistakes in the recovery process.

The first action of any disk recovery is to wipe the target drive you are restoring to, so you don't want to be storing your backup on that same drive unless you are going to be doing recovery of each partition individually, which is then more complicated.  My own preference is to always go with the simplest solution where possible.

Thank you very much sir