Delta E Delta M Practice Quiz: Test Your Energy Calculations

11th Grade

Reviewed by Ekaterina Yukhnovich

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| Questions: 20 | Updated: Mar 12, 2026

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1. The mass equivalent of an energy change Δe is:

Δm = Δe·c²

Δm = Δe/c²

Δm = c²/Δe

Δm = Δe + c²

Concept: mass-equivalent formula. This comes directly from e = mc² by rearranging. It’s used to estimate tiny mass changes from energy changes.

Explanation

Concept: mass-equivalent formula. This comes directly from e = mc² by rearranging. It’s used to estimate tiny mass changes from energy changes.

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About This Quiz

Delta E Delta M Practice Quiz: Test Your Energy Calculations - Quiz

This assessment focuses on Delta E and Delta M concepts, evaluating your ability to perform energy calculations effectively. It tests your understanding of key principles in thermodynamics and energy transfer, making it a valuable resource for students and professionals aiming to enhance their knowledge in energy metrics.

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2. If a system absorbs energy, its mass increases slightly by Δe/c².

True

False

Concept: energy gain ↔ mass gain. Adding energy increases total mass-energy of the system. The increase is usually extremely small.

Explanation

Concept: energy gain ↔ mass gain. Adding energy increases total mass-energy of the system. The increase is usually extremely small.

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3. A device outputs 4.5×10⁶ j. The mass equivalent is closest to:

5×10⁻⁴ kg

5×10⁻⁶ kg

5×10⁻¹¹ kg

5×10⁻¹⁴ kg

Concept: order-of-magnitude estimate. Δm ≈ 4.5×10⁶ / 9×10¹⁶ = 5×10⁻¹¹ kg. This illustrates how small Δm is even for millions of joules.

Explanation

Concept: order-of-magnitude estimate. Δm ≈ 4.5×10⁶ / 9×10¹⁶ = 5×10⁻¹¹ kg. This illustrates how small Δm is even for millions of joules.

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4. Because c² is huge, Δm is usually ______ for everyday energy changes.

Concept: why Δm is small. c² is ~9×10¹⁶, so dividing by it shrinks Δm dramatically. Only huge energy changes make Δm noticeable.

Explanation

Concept: why Δm is small. c² is ~9×10¹⁶, so dividing by it shrinks Δm dramatically. Only huge energy changes make Δm noticeable.

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5. If 2×10⁻⁸ kg of mass were converted to energy, the energy would be about:

1.8×10⁷ j

1.8×10⁹ j

1.8×10¹¹ j

1.8×10¹⁶ j

Concept: e = mc² scaling. e ≈ (2×10⁻⁸)(9×10¹⁶)=1.8×10⁹ j. This is large energy from a tiny mass.

Explanation

Concept: e = mc² scaling. e ≈ (2×10⁻⁸)(9×10¹⁶)=1.8×10⁹ j. This is large energy from a tiny mass.

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6. “Mass defect” is one way to describe small mass differences related to energy in nuclear systems, but e = mc² is the underlying link.

True

False

Concept: underlying principle. Different terms describe contexts, but the fundamental link is mass-energy equivalence. It connects mass differences to energy released or required.

Explanation

Concept: underlying principle. Different terms describe contexts, but the fundamental link is mass-energy equivalence. It connects mass differences to energy released or required.

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7. Which is the best interpretation of “energy has mass-equivalent”?

Energy becomes rest mass automatically

Energy contributes to a system’s total mass-energy and inertia

Energy removes gravity

Energy makes c change

Concept: energy contributes to inertia. In relativity, energy affects how systems behave dynamically. It doesn’t mean energy always becomes matter, but it can contribute equivalently.

Explanation

Concept: energy contributes to inertia. In relativity, energy affects how systems behave dynamically. It doesn’t mean energy always becomes matter, but it can contribute equivalently.

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8. A hot object has slightly more mass than the same object when cold because:

Hot objects contain more atoms

Thermal energy adds to total energy, increasing mass-energy

Heat removes mass

Temperature changes c

Concept: thermal energy and mass. Added internal energy increases total energy. By e = mc², this corresponds to a small mass increase.

Explanation

Concept: thermal energy and mass. Added internal energy increases total energy. By e = mc², this corresponds to a small mass increase.

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9. If a closed box contains light bouncing inside, the energy of that light contributes to the box’s total mass-energy.

True

False

Concept: energy stored in a system. Energy confined in a system counts toward its total energy. In relativity, that total energy is tied to mass-energy.

Explanation

Concept: energy stored in a system. Energy confined in a system counts toward its total energy. In relativity, that total energy is tied to mass-energy.

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10. Which is a common place where mass-energy accounting is essential?

Measuring room temperature

Particle accelerators

Drawing graphs

Ocean tides only

Concept: high-energy contexts. Particle accelerators reach energies comparable to rest energies of particles. Mass-energy equivalence becomes unavoidable.

Explanation

Concept: high-energy contexts. Particle accelerators reach energies comparable to rest energies of particles. Mass-energy equivalence becomes unavoidable.

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11. In SI units, c ≈ 3×10⁸ ______.

Concept: constant value. Using SI units keeps calculations consistent. c is extremely large, driving the huge energy scale.

Explanation

Concept: constant value. Using SI units keeps calculations consistent. c is extremely large, driving the huge energy scale.

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12. A system releases 3×10⁴ j as radiation. Δm is closest to:

3×10⁻⁴ kg

3×10⁻⁸ kg

3×10⁻¹³ kg

3×10⁻¹⁶ kg

Concept: compute Δm. Δm ≈ 3×10⁴ / 9×10¹⁶ ≈ 3.3×10⁻¹³ kg. That’s extremely small.

Explanation

Concept: compute Δm. Δm ≈ 3×10⁴ / 9×10¹⁶ ≈ 3.3×10⁻¹³ kg. That’s extremely small.

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13. E = mc² shows that mass is not an isolated “substance,” but part of energy accounting.

True

False

Concept: mass as energy content. Relativity treats rest mass as one contribution to energy. This reframes how we think about conservation and transformations.

Explanation

Concept: mass as energy content. Relativity treats rest mass as one contribution to energy. This reframes how we think about conservation and transformations.

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14. Which statement is most accurate for ordinary chemical reactions?

Big mass changes occur

Mass changes are real but far too small to measure easily

E = mc² does not apply

Energy is not conserved

Concept: small Δm in chemistry. Chemical energies are relatively small. The corresponding Δm is usually beyond routine measurement.

Explanation

Concept: small Δm in chemistry. Chemical energies are relatively small. The corresponding Δm is usually beyond routine measurement.

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15. Which are correct?

Δm can be found from Δe/c²

Rest energy exists even with no motion

C depends on the observer’s speed

Large energies can correspond to tiny masses

Concept: key tools. c is constant in SR. The huge value of c² makes Δm small unless Δe is enormous.

Explanation

Concept: key tools. c is constant in SR. The huge value of c² makes Δm small unless Δe is enormous.

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16. If energy is conserved in a closed system, then total mass-energy is conserved as well.

True

False

Concept: conservation. Relativity encourages thinking in terms of total energy including rest energy. In closed systems, total remains constant.

Explanation

Concept: conservation. Relativity encourages thinking in terms of total energy including rest energy. In closed systems, total remains constant.

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17. If 0.5 kg of mass could be fully converted to energy, e would be about:

4.5×10⁸ j

4.5×10¹² j

4.5×10¹⁶ j

4.5×10²⁰ j

Concept: scaling again. e = 0.5×9×10¹⁶ = 4.5×10¹⁶ j. This shows the tremendous energy content of mass.

Explanation

Concept: scaling again. e = 0.5×9×10¹⁶ = 4.5×10¹⁶ j. This shows the tremendous energy content of mass.

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18. A careful way to phrase “mass is converted to energy” is:

Mass is destroyed

Some rest mass-energy becomes other forms like radiation/kinetic energy

Energy is created

Time becomes mass

Concept: better wording. The key is transformation, not destruction/creation. Total mass-energy stays accounted for.

Explanation

Concept: better wording. The key is transformation, not destruction/creation. Total mass-energy stays accounted for.

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19. When a system emits light, the emitted light carries away energy and momentum, affecting the system’s energy balance.

True

False

Concept: radiation carries energy. Radiation is not “nothing”; it transports energy and momentum. That’s why it changes the system’s mass-energy.

Explanation

Concept: radiation carries energy. Radiation is not “nothing”; it transports energy and momentum. That’s why it changes the system’s mass-energy.

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20. Grade 11 wrap-up: if you could measure mass extremely precisely, you could detect a mass difference between a charged battery and a discharged battery mainly because:

The casing expands

Stored energy changes the system’s total mass-energy by Δe/c²

C becomes larger in batteries

Electrons stop moving

Concept: energy storage and mass. Stored chemical energy contributes to total energy. A difference in stored energy implies a difference in mass-energy.

Explanation

Concept: energy storage and mass. Stored chemical energy contributes to total energy. A difference in stored energy implies a difference in mass-energy.

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