Answer:
26.8 %
Explanation:
TH = 100°C = 100 + 273 = 373 K
Tc = 0°C = 273 K
The efficiency of the heat engine is given by


η = 0.268
η = 26.8 %
Thus, the efficiency of the heat engine is 26.8 %.
Answer:
C. while the magnet is moving
Explanation:
Electromagnetic induction implies the production of electric current by mere movement of a magnet with respect to a coil or wire.
In the given question, current would be induced in the wire only when the magnet moves. That is either when the magnet is pushed into a wire, or when pulled out. But no current would flow through the wire when the magnet is left there for a while.
The current is induced because of the motion involved. Thus, the appropriate option is C.