Physics 11th Chap 14 : Topic 7 - Maryam Publications

Physics Chapter 14 : Topic 7

Quark Composition of Protons and Neutrons

1 / 30

According to the quark model, a proton is composed of:

A) Two down quarks and one up quark

B) Two up quarks and one down quark

C) One up quark and two strange quarks

D) Three up quarks

2 / 30

The quark composition of a neutron is:

A) $\mathbf{ddd}$

B) $\mathbf{uud}$

C) $\mathbf{udd}$

D) $\mathbf{uuu}$

3 / 30

The total electric charge of a proton can be calculated from:

A) $\mathbf{( + \ 1/3\ e) + ( + \ 1/3\ e) + ( - \ 2/3\ e}\mathbf{)}$

B) $\mathbf{( - \ 2/3\ e) + ( - \ 2/3\ e) + ( + \ 1/3\ e)}$

C) $\mathbf{( + \ e) + ( + \ e) + ( - \ e)}$

D) $\mathbf{( + \ 2/3\ e) + ( + \ 2/3\ e) + ( - \ 1/3\ e)}$

4 / 30

The net charge of a neutron is zero because:

A) It contains only neutral quarks.

B) It contains no quarks.

C) Its mass removes its charge.

D) Its quark charges cancel each other.

5 / 30

Which combination represents a proton?

A) $\mathbf{u + u + d}$

B) $\mathbf{d + d + d}$

C) $\mathbf{u + d + d}$

D) $\mathbf{u + s + d}$

6 / 30

The charge of an up quark is:

A) $\mathbf{- \ 2/3\ e}$

B) $\mathbf{+ \ 2/3\ e}$

C) $\mathbf{+ \ 1/3\ e}$

D) $\mathbf{- \ 1/3\ e}$

7 / 30

Which combination represents a neutron?

A) $\mathbf{d + s + s}$

B) $\mathbf{u + d + d}$

C) $\mathbf{u + u + u}$

D) $\mathbf{u + u + d}$

8 / 30

The charge of a down quark is:

A) $\mathbf{+ \ 2/3\ e}$

B) $\mathbf{+ \ 1/3\ e}$

C) $\mathbf{- \ 2e}$

D) $\mathbf{- \ 1/3\ e}$

9 / 30

A particle made of two up quarks and one down quark will have charge:

A) $\mathbf{+ \ e}$

B) $\mathbf{- \ e}$

C) Zero

D) $\mathbf{+ \ 2e}$

10 / 30

A particle made of one up quark and two down quarks will have charge:

A) Zero

B) $\mathbf{+ \ 2e}$

C) $\mathbf{+ \ e}$

D) $\mathbf{- \ e}$

11 / 30

Protons and neutrons are classified as:

A) Photons

B) Mesons

C) Leptons

D) Baryons

12 / 30

A baryon is a particle made of:

A) Two quarks

B) Three quarks

C) One quark

D) 1 quark and 1 antiquark

13 / 30

The difference between a proton and neutron is mainly due to:

A) Different arrangement of up and down quarks

B) Absence of strong force

C) Presence of electrons

D) Different number of quarks

14 / 30

Which statement about proton and neutron composition is correct?

A) Proton has more down quarks than neutron

B) Proton and neutron contain identical quarks in identical numbers

C) Neutron contains no quarks

D) Neutron has more down quarks than proton

15 / 30

The charge of a proton arises because:

A) Neutrons create positive charge.

B) Quarks have no charge.

C) Only electrons contribute charge.

D) Quarks have fractional charges that add to $\mathbf{+ \ e}$.

16 / 30

If the down quark charge is $\mathbf{- \ 1/3\ e}$, then two down quarks together have charge:

A) $\mathbf{+ \ 2/3\ e}$

B) $\mathbf{- \ 1/3\ e}$

C) $\mathbf{- \ 2/3\ e}$

D) $\mathbf{+ \ 1e}$

17 / 30

If two up quarks are present in a proton, their combined charge is:

A) $\mathbf{+ \ 1/3\ e}$

B) $\mathbf{- \ 4/3\ e}$

C) $\mathbf{+ \ 4/3\ e}$

D) $\mathbf{+ \ 2/3\ e}$

18 / 30

Which quark combination produces a neutral baryon?

A) $\mathbf{uuu}$

B) $\mathbf{udd}$

C) $\mathbf{udd}$ with extra electron

D) $\mathbf{udd}$

19 / 30

A proton changes into a neutron. Which quark change occurs?

A) A down quark changes into an up quark.

B) All quarks disappear.

C) A quark changes into a photon.

D) An up quark changes into a down quark.

20 / 30

A neutron changes into a proton during beta-minus decay. The quark-level change is:

A) $\mathbf{u\ }\overset{\mathbf{\ \ \ \ \ \ \ \ \ \ \ \ }}{\rightarrow}\mathbf{\ d}$

B) $\mathbf{d\ }\overset{\mathbf{\ \ \ \ \ \ \ \ \ \ \ \ }}{\rightarrow}\mathbf{\ c}$

C) $\mathbf{d\ }\overset{\mathbf{\ \ \ \ \ \ \ \ \ \ \ \ }}{\rightarrow}\mathbf{\ u}$

D) $\mathbf{u\ }\overset{\mathbf{\ \ \ \ \ \ \ \ \ \ \ \ }}{\rightarrow}\mathbf{\ s}$

21 / 30

Which particles have the same quark content?

A) Neutron and photon

B) Proton and electron

C) Proton and positron

D) Proton and neutron

22 / 30

A proton contains how many up quarks?

A) Two

B) Zero

C) Three

D) One

23 / 30

A neutron contains how many down quarks?

A) One

B) Zero

C) Three

D) Two

24 / 30

Which statement is correct about the masses of proton and neutron?

A) Their masses are mainly related to energy of quark interactions.

B) Quarks have no role in their mass.

C) Their masses come only from quark rest masses.

D) Proton has no quarks.

25 / 30

A particle has composition $\mathbf{uuu}$. Its charge would be:

A) $\mathbf{+ \ 2e}$

B) Zero

C) $\mathbf{- \ e}$

D) $\mathbf{+ \ e}$

26 / 30

A particle has composition $\mathbf{ddd}$. Its charge would be:

A) $\mathbf{- \ e}$

B) $\mathbf{+ \ e}$

C) $\mathbf{+ \ 2e}$

D) Zero

27 / 30

Which statement explains why a neutron is neutral?

A) It contains only electrons.

B) It contains no charged particles.

C) It has no mass.

D) The positive and negative fractional quark charges cancel.

28 / 30

The quark model explains that:

A) Electrons are made of protons.

B) Protons are fundamental particles with no structure.

C) Protons and neutrons are made of smaller particles called quarks.

D) Photons contain quarks.

29 / 30

Which of the following correctly compares proton and neutron?

A) Both: $\mathbf{uuu}$

B) Proton: $\mathbf{udd}$, Neutron: $\mathbf{uud}$

C) Both: $\mathbf{ddd}$

D) Proton: $\mathbf{uud}$, Neutron: $\mathbf{udd}$

30 / 30

The reason protons and neutrons are not considered fundamental particles is that:

A) They have no charge.

B) They are made of quarks.

C) They have no mass.

D) They cannot interact.

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