Physics 11th Chap 14 : Topic 16 - Maryam Publications

Physics Chapter 14 : Topic 16

Annihilation Reactions

1 / 35

An annihilation reaction occurs when:

A) A particle loses its electric charge

B) A particle meets its corresponding antiparticle and their mass is converted into energy

C) A nucleus splits into smaller nuclei

D) Two identical particles combine to form a heavier particle

2 / 35

The most common example of annihilation reaction is:

A) Proton-proton collision

B) Electron-positron collision

C) Neutron-electron collision

D) Photon-photon collision

3 / 35

When an electron and positron annihilate completely, their mass is converted into:

A) Heat and light energy

B) Electrical charge

C) Only kinetic energy of electrons

D) Neutrons only

4 / 35

The energy released during annihilation is explained by:

A) Conservation of momentum only

B) Einstein’s mass-energy equivalence relation

C) Newton’s second law

D) Ohm’s law

5 / 35

In an electron-positron annihilation, the produced particles are commonly:

A) Protons

B) Neutrons

C) Atoms

D) Photons

6 / 35

Which condition is necessary for an annihilation reaction?

A) Particles must be stationary.

B) Particles must have zero mass.

C) Two particles must have the same charge.

D) A particle must meet its corresponding antiparticle.

7 / 35

During annihilation, which quantity is conserved?

A) Mass alone

B) Energy only

C) Total energy and momentum

D) Electric charge is destroyed

8 / 35

The rest mass of an electron and positron is converted into:

A) Energy

B) Nothing

C) Negative mass

D) Electric charge

9 / 35

If a particle meets its antiparticle, the result is usually:

A) Permanent storage of energy

B) Creation of only electrons

C) Annihilation reaction

D) Formation of a larger atom

10 / 35

Complete annihilation means:

A) All mass is converted into energy.

B) Some mass remains as particles.

C) Energy becomes zero.

D) Charge disappears without energy release.

11 / 35

Partial annihilation occurs when:

A) Only heat is produced.

B) Particles disappear without energy conversion.

C) No energy is produced.

D) Some mass remains as new subatomic particles.

12 / 35

When an electron and positron annihilate, the total electric charge before and after reaction is:

A) Reduced to zero because charge is destroyed

B) Converted into mass

C) Increased

D) Conserved

13 / 35

Which equation represents the conversion of mass into energy?

A) $\mathbf{E =}\mathbf{mc}^{\mathbf{2}}$

B) $\mathbf{V = IR}$

C) $\mathbf{F = ma}$

D) $\mathbf{p = mv}$

14 / 35

A positron is the antiparticle of:

A) Photon

B) Electron

C) Neutron

D) Proton

15 / 35

Two photons produced in electron-positron annihilation carry:

A) No energy

B) Only electric charge

C) The energy of the original masses

D) Negative mass

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Why can electron and positron annihilate each other?

A) They have different masses.

B) They have identical charges.

C) They are particle-antiparticle partners.

D) They cannot interact.

17 / 35

Which reaction represents annihilation?

A) $\mathbf{n\ \ }\overset{\mathbf{\ \ \ \ \ \ \ \ \ \ \ \ \ \ }}{\rightarrow}\mathbf{\ \ }\mathbf{p +}\mathbf{e}^{\mathbf{-}}$

B) $\mathbf{p + n\ \ }\overset{\mathbf{\ \ \ \ \ \ \ \ \ \ \ \ \ \ }}{\rightarrow}\mathbf{\ \ \ }$nucleus

C) $\mathbf{H}_{\mathbf{2}}\mathbf{\ \ }\overset{\mathbf{\ \ \ \ \ \ \ \ \ \ \ \ \ \ }}{\rightarrow}\mathbf{\ \ }\mathbf{H + H}$

D) $\mathbf{e}^{\mathbf{-}}\mathbf{+}\mathbf{e}^{\mathbf{+}}\mathbf{\ \ }\overset{\mathbf{\ \ \ \ \ \ \ \ \ \ \ \ \ \ }}{\rightarrow}\mathbf{\ \ }\mathbf{\gamma + \gamma}$

18 / 35

The energy produced in annihilation is usually very large because:

A) A small amount of mass is converted using $\mathbf{c}^{\mathbf{2}}$.

B) Charges become larger.

C) Particles gain extra mass.

D) Particles move very slowly.

19 / 35

In a complete annihilation reaction, the final products are usually:

A) Electrons only

B) Electromagnetic radiation

C) Heavy nuclei

D) Quarks only

20 / 35

Which statement about annihilation is correct?

A) Antimatter has no effect on matter.

B) Energy conservation is violated.

C) Matter disappears without producing energy.

D) Mass can be converted into energy.

21 / 35

If the mass of particles involved in annihilation increases, the released energy:

A) Increases

B) Becomes zero

C) Decreases

D) Remains unchanged

22 / 35

Which pair can undergo annihilation?

A) Proton and electron

B) Electron and positron

C) Electron and photon

D) Proton and neutron

23 / 35

During annihilation, the original particles:

A) Lose only their charge

B) Become heavier

C) Remain unchanged

D) Transform into other forms of energy or particles

24 / 35

Annihilation reactions support the idea that:

A) Mass is always conserved separately.

B) Matter and energy are unrelated.

C) Energy cannot change form.

D) Matter can be converted into energy.

25 / 35

If some mass remains after annihilation, it appears as:

A) New subatomic particles

B) Empty space

C) Lost energy

D) Electric current only

26 / 35

Which conservation law prevents charge from disappearing during annihilation?

A) Conservation of volume

B) Conservation of momentum

C) Conservation of temperature

D) Conservation of charge

27 / 35

In electron-positron annihilation, why are photons produced instead of electrons?

A) Photons have negative mass.

B) Charge conservation requires conversion into neutral energy carriers.

C) Electrons cannot exist.

D) Positrons become photons only.

28 / 35

A particle and antiparticle have equal masses. During annihilation:

A) Their entire mass may become energy.

B) Their charges add to create matter.

C) Their energy becomes zero.

D) Their masses increase.

29 / 35

Which statement about matter-antimatter annihilation is FALSE?

A) It violates conservation of energy.

B) It releases energy.

C) It may produce photons.

D) It involves antiparticles.

30 / 35

The main significance of annihilation reactions is that they demonstrate:

A) Energy and mass are interchangeable.

B) Atoms are indivisible.

C) Particles have no structure.

D) Gravity controls particles.

31 / 35

When a proton meets an antiproton, the possible result is:

A) No interaction

B) Annihilation producing energy and new particles

C) Formation of only electrons

D) Permanent storage of mass

32 / 35

The energy released from annihilation is greater than ordinary chemical reactions because:

A) Annihilation converts rest mass directly into energy.

B) Nuclear particles have no energy.

C) Chemical reactions convert all mass into energy.

D) Photons have no energy.

33 / 35

If an electron and positron are both at rest before annihilation, the resulting photons must:

A) Have mass equal to electrons

B) Have total momentum equal to zero

C) Have negative charge

D) Have no energy

34 / 35

Which reaction represents partial annihilation?

A) Matter $\overset{\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ }{\rightarrow}$ energy only

B) Matter $\mathbf{+}$ antimatter $\overset{\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ }{\rightarrow}$ photons only

C) Matter $\mathbf{+}$ antimatter $\overset{\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ }{\rightarrow}$ energy $\mathbf{+}$ new particles

D) Particle $\overset{\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ }{\rightarrow}$ nothing

35 / 35

The ultimate source of energy in annihilation reactions is:

A) Temperature of particles

B) External heat supply

C) Electric charge only

D) The rest mass of particles

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