6.
t
A DC power source set to 12.0 V is connected to a heating coil. The coil is immersed
in 250 mL water in a beaker. The water is initially at 16.7 °C. A current of 3.5 A
flows constantly through the heating coil for 4 minutes exactly, after which time the
temperature of the water rises to 22.7 °C.
The efficiency of the heating coil in heating the water is closest to:
(A) 15%
(B)
62%
(C)
76%
(D) 84%