Specific heat capicity of water is 4200Jkg-1 C-1 . what its meaning .

The specific heat capacity of water is 4,200 Joules per kilogram per degree Celsius (J/kg°C). This means that it takes 4,200 J to raise the temperature of 1 kg of water by 1°C. Lead will warm up and cool down faster because it doesn't take much energy to change its temperature.

r=rho l/a where a is the area, l is the length and rho is resistivity so the greater the area the lesser the resistance thats why the earth pin is thicker bcos current follow the shortest path, so less resistive .

like poles repel so keep pushing north to north and repels funny to see this