Energy (Physics Paper 1) Flashcards

What does the specific heat capacity of a substance tell you?

Answer: The energy needed to raise the temperature of 1 kg of the substance by 1 °C

Specific heat capacity is the energy required to raise the temperature of 1 kg of a substance by 1 °C, measured in J/kg °C.

How much energy is needed to raise the temperature of 0.5 kg of water from 20 °C to 60 °C? (Specific heat capacity of water = 4200 J/kg °C)

Answer: 84,000 J

ΔE = m c Δθ = 0.5 × 4200 × (60 − 20) = 0.5 × 4200 × 40 = 84,000 J.

Which statement about the principle of conservation of energy is correct?

Answer: Energy can be transferred usefully, stored or dissipated, but cannot be created or destroyed

Energy is conserved: the total energy in a closed system stays the same, it is only transferred between stores or dissipated.

Which of these changes would reduce the rate of thermal energy transfer from a house?

Answer: Installing loft insulation with a low thermal conductivity

Insulation with a low thermal conductivity slows the rate at which energy is conducted out of the building.

A spring with a spring constant of 200 N/m is stretched by 0.1 m. How much elastic potential energy is stored?

Answer: 1 J

Ee = ½ k e² = 0.5 × 200 × 0.1² = 0.5 × 200 × 0.01 = 1 J.

Which is an advantage of using nuclear power stations rather than coal-fired power stations for generating electricity?

Answer: Nuclear power stations produce no carbon dioxide during generation

Nuclear reactors do not burn fuel, so they release no carbon dioxide while generating electricity, unlike coal.