The efficiency of a heat engine is given by the expression 
The efficiency of a heat engine is the ratio of the work done by the engine to the heat given as the input to the engine.

The heat engine absorbs Q h from the hot reservoir , performs a work <em>W</em> on the absorbed heat and rejects Qc to the cold reservoir.
Therefore, the work done is given by,

Thus the efficiency is given by, 
Answer:
the elements are made up of only one kind of atom, the compounds consist of two or more elements that are chemically combined, and the mixtures are physical combination of two or more substances
Since the lamps are identical, the current divides equally through them... 0.6A through each lamp.
Momentum before the hit:
p = mv = 0.01 * 300 + 1 * 0
Momentum after the hit:
p = 0.01 * 150 + 1 * v
Momentum is conserved:
0.01 * 300 = 0.01 * 150 + v
3 = 1.5 + v
v = 1.5
The velocity of the block after the collision is 1.5 m/s.