Question detail

If 2 kg of water is heated from 20°C to 100°C, what is the change in thermal energy if the specific heat capacity of water is 4.2 J/kg°C?

Try the question, check the answer, then read the explanation to understand the curriculum point.

Show answer Topic hub Objective page

At a glance

MCQ

Type

practice

Style

Topic

Energy changes in a system, and the ways energy is stored before and after such changes

Question

A. 672 J
B. 840 J
C. 1680 J
D. 8400 J

Answer

672 J

Explanation

The correct option is "672 J". 672 J is right because it directly matches Energy changes in systems: Identify change in thermal energy in joules, mass in kilograms, specific heat capacity in joules per kilogram per degree Celsius and temperature change in degrees Celsius.. The other options are less suitable because they change the required Physics relationship, confuse the relevant energy store or use a distractor that does not answer the question.

Common mistake

Confusing Units of Measurement

Students often confuse joules with kilograms when identifying thermal energy changes.

Always remember that thermal energy is measured in joules, while mass is measured in kilograms. Keep the units distinct when performing calculations.

Related flashcards

Flashcard 1 of 5

Press Space to flip, arrows to move