For how many years could a 100-watt bulb burn, using the energy produced by the annihilation of 1 gram of matt

Question

For how many years could a 100-watt bulb burn, using the energy produced by the annihilation of 1 gram of matter? (A 100-watt bulb uses 10^9 ergs/sec; 1 year ~= 10^7 sec.)

Answer 1

Energy from 1 gram of matter (0.001 kg)

E = m* c^2
E in Joules
m in kg
c^2 in (meters/sec)^2

E = 0.001 * (3 * 10^8)^2
E = 9 * 10^13 Joules

Power [Watts] = Joules/sec
Joules / Watts = seconds

9 * 10^13 / 100 = seconds

9 * 10^11 seconds is the time

9 * 10^4 years : 90,000 years approximately.

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Answer 2

TLBS gives you the best answer (and gets my vote when that time comes).

If you bleed 1/2 gram of antimatter onto matter, you can annihilate a total of 1 gram.

Some of this energy will be lost as waste heat--TLBS's answer assumes no loss (I think). It is thus an upper limit. Assuming a 60% efficiency, well, you can work out the rest.

Answer 3

Until the bulb burns out -- about 6,000 hours if you're lucky.

Answer 4

28 499 years

but unfortunately you cannot just anihilate matter - it violates quantum conservation laws

Answer 5

for eternity. time doesnt exist. :)

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