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and a cold tank temperature 
. The temperature of the hot tank of the first machine is increased by 
and the temperature of the cold tank of the second machine is decreased by 
the initial temperature of the hot tank is 200 °C.
. The useful sound and light power emitted by the television is 
. What is the efficiency of the television?
of energy is emitted as thermal energy for every 
of energy emitted as light. What is the efficiency of the lamp, as the percentage of electrical energy converted to light energy?
and a wasted power of 
. What is the efficiency of the system?
wastes 
of power. What is the useful output power of the system?
of mechanical output power. The efficiency of the motor is 
. Which row is correct?
, acting on a car of mass 
, moves the car up the slope through a distance 
at constant velocity 
. The angle of the slope to the horizontal is 
.
of energy is emitted as thermal energy for every 
of energy emitted as light. What is the efficiency of a filament lamp, as the percentage of electrical energy converted to light energy?
power supply for 
to charge the battery. The efficiency of the charging process is 
. What is the total energy stored in the battery?
of electrical power when raising water. The pumping system lifts 
of water per second through a vertical height of 
. What is the efficiency of the pumping system?
. Energy 
is wasted and the remaining energy does useful work. What is the efficiency of the motor?
. Old-type filament lamps have an efficiency of 
. The two types of lamps produce the same useful output power.
?
of useful mechanical output power. The efficiency of the motor is 
. Which row is correct?
in a process is partly transferred to useful energy output 
and partly transferred to energy that is wasted 
. What is the efficiency of the process?
