The national grid supplied a house with 18000000 j of energy in 1 hour. what was the average current supplied to the house in that hour? write any equations that you use.

Electrical power  =  (voltage) x (current)

Electrical energy  =  (power) x (time)

Combine those definitions:

             Energy  =  (voltage) x (current) x (time)

Divide each side by (voltage x time), and we have

             Current  =  Energy / (voltage x time)

You told us that

             Energy = 1.8 x 10⁷ joules

             Time  =  1 hour  =  3,600 seconds

so we have 

             Current  =  (1.8 x 10⁷) / (voltage x 3,600).

If you live in the US, Canada, or Mexico, your voltage is 120 volts.

             Current = (1.8 x 10⁷) / (120 x 3,600)  =  41-2/3 Amperes

If you live practically anywhere else in the world, your voltage is 240 volts.

              Current = (1.8 x 10⁷) / (240 x 3,600)  =  20-5/6 Amperes. 

Aform of energy that is reflected or emitted from objects in the form of electrical and magnetic waves that can travel through space. there are many forms of  electromagnetic  energy including gamma rays, x rays, ultraviolet radiation, visible light, infrared radiation, microwaves and radio waves.