Physics 11th Chap 14 : Topic 16 - Maryam Publications

Physics Chapter 14 : Topic 16

Annihilation Reactions

1 / 35

An annihilation reaction occurs when:

A) A nucleus splits into smaller nuclei

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

C) A particle loses its electric charge

D) Two identical particles combine to form a heavier particle

2 / 35

The most common example of annihilation reaction is:

A) Photon-photon collision

B) Electron-positron collision

C) Proton-proton collision

D) Neutron-electron collision

3 / 35

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

A) Neutrons only

B) Only kinetic energy of electrons

C) Electrical charge

D) Heat and light energy

4 / 35

The energy released during annihilation is explained by:

A) Conservation of momentum only

B) Ohm’s law

C) Newton’s second law

D) Einstein’s mass-energy equivalence relation

5 / 35

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

A) Atoms

B) Protons

C) Photons

D) Neutrons

6 / 35

Which condition is necessary for an annihilation reaction?

A) Particles must be stationary.

B) Two particles must have the same charge.

C) Particles must have zero mass.

D) A particle must meet its corresponding antiparticle.

7 / 35

During annihilation, which quantity is conserved?

A) Mass alone

B) Energy only

C) Electric charge is destroyed

D) Total energy and momentum

8 / 35

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

A) Electric charge

B) Nothing

C) Negative mass

D) Energy

9 / 35

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

A) Annihilation reaction

B) Formation of a larger atom

C) Permanent storage of energy

D) Creation of only electrons

10 / 35

Complete annihilation means:

A) Energy becomes zero.

B) Charge disappears without energy release.

C) All mass is converted into energy.

D) Some mass remains as particles.

11 / 35

Partial annihilation occurs when:

A) Some mass remains as new subatomic particles.

B) Particles disappear without energy conversion.

C) No energy is produced.

D) Only heat is produced.

12 / 35

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

A) Conserved

B) Reduced to zero because charge is destroyed

C) Converted into mass

D) Increased

13 / 35

Which equation represents the conversion of mass into energy?

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

B) $\mathbf{F = ma}$

C) $\mathbf{V = IR}$

D) $\mathbf{p = mv}$

14 / 35

A positron is the antiparticle of:

A) Proton

B) Neutron

C) Electron

D) Photon

15 / 35

Two photons produced in electron-positron annihilation carry:

A) Negative mass

B) Only electric charge

C) No energy

D) The energy of the original masses

16 / 35

Why can electron and positron annihilate each other?

A) They have identical charges.

B) They are particle-antiparticle partners.

C) They have different masses.

D) They cannot interact.

17 / 35

Which reaction represents annihilation?

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

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

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

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

18 / 35

The energy produced in annihilation is usually very large because:

A) Particles gain extra mass.

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

C) Charges become larger.

D) Particles move very slowly.

19 / 35

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

A) Quarks only

B) Electrons only

C) Heavy nuclei

D) Electromagnetic radiation

20 / 35

Which statement about annihilation is correct?

A) Antimatter has no effect on matter.

B) Energy conservation is violated.

C) Mass can be converted into energy.

D) Matter disappears without producing energy.

21 / 35

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

A) Increases

B) Remains unchanged

C) Becomes zero

D) Decreases

22 / 35

Which pair can undergo annihilation?

A) Electron and positron

B) Electron and photon

C) Proton and electron

D) Proton and neutron

23 / 35

During annihilation, the original particles:

A) Lose only their charge

B) Transform into other forms of energy or particles

C) Become heavier

D) Remain unchanged

24 / 35

Annihilation reactions support the idea that:

A) Energy cannot change form.

B) Matter can be converted into energy.

C) Matter and energy are unrelated.

D) Mass is always conserved separately.

25 / 35

If some mass remains after annihilation, it appears as:

A) New subatomic particles

B) Empty space

C) Electric current only

D) Lost energy

26 / 35

Which conservation law prevents charge from disappearing during annihilation?

A) Conservation of charge

B) Conservation of volume

C) Conservation of temperature

D) Conservation of momentum

27 / 35

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

A) Charge conservation requires conversion into neutral energy carriers.

B) Photons have negative mass.

C) Electrons cannot exist.

D) Positrons become photons only.

28 / 35

A particle and antiparticle have equal masses. During annihilation:

A) Their masses increase.

B) Their entire mass may become energy.

C) Their energy becomes zero.

D) Their charges add to create matter.

29 / 35

Which statement about matter-antimatter annihilation is FALSE?

A) It releases energy.

B) It involves antiparticles.

C) It violates conservation of energy.

D) It may produce photons.

30 / 35

The main significance of annihilation reactions is that they demonstrate:

A) Gravity controls particles.

B) Particles have no structure.

C) Atoms are indivisible.

D) Energy and mass are interchangeable.

31 / 35

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

A) Permanent storage of mass

B) No interaction

C) Annihilation producing energy and new particles

D) Formation of only electrons

32 / 35

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

A) Annihilation converts rest mass directly into energy.

B) Chemical reactions convert all mass into energy.

C) Nuclear particles have no 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 negative charge

C) Have no energy

D) Have total momentum equal to zero

34 / 35

Which reaction represents partial annihilation?

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

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

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

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

35 / 35

The ultimate source of energy in annihilation reactions is:

A) External heat supply

B) The rest mass of particles

C) Temperature of particles

D) Electric charge only

Your score is

0%