Answer:
0.424
Explanation:
The electrical energy is the electrical power times time:
E = Pt
E = (IV)t
E = (1.5 A) (110 V) (300 s)
E = 49,500 J
The heat absorbed by the cookie dough is the mass times specific heat capacity times increase in temperature:
Q = mCΔT
Q = (1 kg) (4200 J/kg/K) (5 K)
Q = 21,000 J
So the fraction of electrical energy converted to internal energy is:
Q / E = 21,000 / 49,500
Q / E = 0.424
The remainder of the electrical energy is used to do work.
