Heat energy
Energy is measured using the unit Joule (J). Temperature is measured using the unit degree Celsius °C). To increase the temperature of 1 liter of water by 1 °C, 4200 J of heat energy is required.
(a) Kelly wants to increase the temperature of 2 liters of water from 25 °C to 100 °C.
(1) Find the amount of heat energy required.
(ii) The energy efficiency of an electric kettle A is 60%; that is, it requires 1 J of electrical energy to produce 0.6 J of heat energy. Find the amount of electrical energy kettle A requires.
(b) Another electric kettle B requires 80% of the electrical energy used by electric kettle A. Find the energy efficiency of electric kettle B.
Your answer:
(a) Kelly wants to increase the temperature of 2 liters of water from 25 °C to 100 °C.
(1) Find the amount of heat energy required.
(ii) The energy efficiency of an electric kettle A is 60%; that is, it requires 1 J of electrical energy to produce 0.6 J of heat energy. Find the amount of electrical energy kettle A requires.
(b) Another electric kettle B requires 80% of the electrical energy used by electric kettle A. Find the energy efficiency of electric kettle B.
Your answer:
Tips for related online calculators
Our percentage calculator will help you quickly and easily solve a variety of common percentage-related problems.
Tip: Our volume units converter will help you convert volume units.
Tip: Our volume units converter will help you convert volume units.
You need to know the following knowledge to solve this word math problem:
basic operations and conceptsUnits of physical quantitiesthemes, topicsGrade of the word problem
Related math problems and questions:
- Heating water
5 kg of water warmed up by 10 °C. How much heat did the water absorb? (Remember that 1 kg of water requires 4,200 J of heat to raise its temperature by 1 °C.) - The bath
The bath has water with a volume of 220 l and a temperature of 65 °C. Find the mass m2 of water at 15 °C to be poured, so the resulting temperature in the bath will be 40 °C. We neglect the heat exchange between water and the environment. Water - Electric cooker
During which time does an electric cooker with power input P = 500 W and efficiency n = 75% heat water with mass m = 2 kg and temperature t1 = 10 °C to the boiling point (t2 = 100 °C)? The specific heat capacity of water is c = 4 180 J/kg/K. - Transformer oil temperature
The transformer is oil-cooled and transforms a power of 20 MW with an efficiency of 92%. Determine the temperature of the oil at the outlet of the transformer if the oil was 20 °C when it entered the transformer. 2.5 liters of oil will flow through the tr - Iron key temperature
By how much °C will the temperature of an iron key weighing 0.004 t change if it receives 360,000 J of heat? ( c of iron is 450 J/kg.°C ) - Ice to boiling water
Calculate the heat needed to convert 5 kg of ice at a temperature of -5 °C to water with a temperature of 100 °C. c (water) = 4200 J/°C/kg, c (ice) = 2100 J/°C/kg. The mass group heat of solidification of water is l = 334 kJ/kg. Calculate the heat that 1k - Heating Liquid Graph Analysis
Colorless liquid weighing m = 200 g is heated with constant stirring on a stove with power input P0 = 600 W. 80% of the supplied energy is used to heat the liquid. Selected measured values of liquid temperature as a function of time are recorded in the ta
