The unit of energy is?
  • Watt
  • Kilojoule
  • Kilogramme
  • Volt
Complete the statement about the principal of Conservation of Energy.Energy can be changed for one form to another but the total amount of energy
  • always increases
  • always decreases
  • does not change
  • varies according to the reaction
Conservation of Energy Questions. Example: A battery releases 100J of energy to a lamp. The lamp releases 80J of energy as light but it also releases heat energy. How much heat energy is released? Answer=20J ( If he total energy input is 100 and 80 is the output as light, that means that 20 J is left as heat 100J-80J=20J)..Now try these questions..Question. A battery releases 200J of energy to a lamp. the energy is converted to heat and light. 50kJ is given out as heat. How much is released as Light?
  • 100J
  • 150J
  • 200J
  • 250J
A Radio releases 250J of energy 10J is released as heat , How much is released as sound?
  • 200J
  • 220J
  • 240J
  • 260J
A torch battery releases 50J of energy as heat and 240J as light, What is the total energy released from the battery?
  • 250J
  • 280J
  • 290J
  • 300J
The % energy efficiency of an appliance is
  • total energy input/ useful energy output x 100
  • useful energy output /total energy input x100
  • total energy input x useful energy input x100
  • useful energy output /total energy input x50
In a filament bulb the electical power input is 40W andthe light (Useful) energy output is 4W. What is the % efficiency?
  • 1%
  • 10%
  • 0.1%
  • 4%
In a modern low energy bulb, the the electrical power input is 12W and the Light (useful) power output is 4W. What is the energy efficiency of this bulb?
  • 3%
  • 25.5%
  • 30%
  • 33.3%
This one is harder.. you need to decide what is the 'useful' energy output. A TV takes in 600J of electrical energy and gives out 300J of light, 240J of sound and 60J of heat energy (be careful here!
  • 9%
  • 60%
  • 90%
  • 85%
(Higher level only)What is the Formula to calculate energy transfer for Kinetic Energy?
  • Ek=1/2 mv2
  • 1/2mv=k
  • Em2=1/2k
  • EK2 =2mv
0:0:1



Answered

Not Answered

Not Visited
Correct : 0
Incorrect : 0