>>> my laptop is connected to my mobile hotspot. <<<
this means your laptop is connected via the moblie network to the internet, this network is outside your router
>>> My pc is connected to router through ethernet port <<<
this suggests your router is probably performing NAT between your internal network and the public internet
1) you need to determine the public IP-address used by your router
NB! this address can change from time to time, as mostly this is issued dynamically by your provider using DHCP
You must use this ip addres as ping destination
2) on your router you need to enable port-forwarding from internet to PC to enable incoming connections
read the manual of your router how to do this for ping (ICMP)
You must include this port in your ping command also
3) on your PC in the windows firewall you need to allow ping incoming from other subnets than the local subnet
