Does tetra joule equal mega joule?

One million. Mega means one million or 106, as also in megawatts.

simply by multiplying by 10 exponent 6 !

Watts are measured in Joules and a joule is work divided by time. (w/sec)

The fun answer is: 0,01 kilojoule The serious answer is: 1 kilogram meter2/second2

1 million.