Q.1.
Calculate the efficiency of a heater which can convert 700 joules of chemical energy into 175 joules of heat energy.
Q.2.
Which formula can be used to calculate the percentage of energy transferred by a device?
Q.3.
What cannot be done to energy?
Q.4.
What happens to wasted energy?
Q.5.
A solar panel is 20% efficient at converting light energy into electricity. If it generates 200 joules of electrical power, how much power is wasted?
Q.6.
A wind turbine generates 100 joules of electricity from a gust of wind which has 300 joules of energy. How efficient is the turbine?
Q.7.
Which formula can be used to calculate the percentage of power transferred by a device?
Q.8.
During an energy transfer, only part of it may be usefully transferred. What happens to the remainder of the unused energy?
Q.9.
An LED converts around 80% of the energy supplied to it into light. How much energy is converted into light if a total of 50 J is supplied to it?
Q.10.
What can be done to energy?