Elementary Particles and Symmetries - Nuclear and Particle Physics - Physics Previous Year Questions

1

2007 · Physics · Nuclear and Particle Physics · Elementary Particles and Symmetries

Physics (PH) 2007

The strangeness quantum number is conserved in

A

strong, weak and electromagnetic interactions.

B

weak and electromagnetic interactions only.

C

strong and weak interactions only.

D

strong and electromagnetic interactions only.

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2

2007 · Physics · Nuclear and Particle Physics · Elementary Particles and Symmetries

Physics (PH) 2007

A relativistic particle travels a length of \( 3 \times 10^{-3} \) m in air before decaying. The decay process of the particle is dominated by

A

strong interactions.

B

electromagnetic interactions.

C

weak interactions.

D

gravitational interactions.

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3

2007 · Physics · Nuclear and Particle Physics · Elementary Particles and Symmetries

Physics (PH) 2007

The strange baryon \( \Sigma^+ \) has the quark structure

A

\(uds \)

B

\(uud \)

C

\(uus \)

D

\(u\bar{s} \)

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4

2007 · Physics · Nuclear and Particle Physics · Elementary Particles and Symmetries

Physics (PH) 2007

A relativistic particle travels a length of \(3 \times 10^{-3}\) m in air before decaying. The decay process of the particle is dominated by

A

strong interactions.

B

electromagnetic interactions.

C

weak interactions.

D

gravitational interactions.

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5

2007 · Physics · Nuclear and Particle Physics · Elementary Particles and Symmetries

Physics (PH) 2007

The strange baryon \(\Sigma^+\) has the quark structure

A

\(uds\)

B

\(uud\)

C

\(uus\)

D

\(u\bar{s}\)

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6

2008 · Physics · Nuclear and Particle Physics · Elementary Particles and Symmetries

Physics (PH) 2008

According to the quark model, the K⁺ meson is composed of the following quarks:

A

\(u \bar{u} d\)

B

\(u \bar{s}\)

C

\(u \bar{s}\)

D

\(s \bar{u}\)

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7

2008 · Physics · Nuclear and Particle Physics · Elementary Particles and Symmetries

Physics (PH) 2008

Choose the correct statement from the following:

A

The reaction \(K^+ K^- \rightarrow p \bar{p}\) can proceed irrespective of the kinetic energies of \(K^+\) and \(K^-\).

B

The reaction \(K^+ K^- \rightarrow p \bar{p}\) is forbidden by the baryon number conservation.

C

The reaction \(K^+ K^- \rightarrow 2\gamma\) is forbidden by strangeness conservation.

D

The decay \(K^0 \rightarrow \pi^+ \pi^-\) proceeds via weak interactions.

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8

2008 · Physics · Nuclear and Particle Physics · Elementary Particles and Symmetries

Physics (PH) 2008

A neutral pi meson (\(\pi^0\)) has a rest-mass of approximately 140 MeV/c² and a lifetime of \(\tau\) sec. A \(\pi^0\) produced in the laboratory is found to decay after 1.25 \(\tau\) sec into two photons. Which of the following sets represents a possible set of energies of the two photons as seen in the laboratory?

A

70 MeV and 70 MeV

B

35 MeV and 100 MeV

C

75 MeV and 100 MeV

D

25 MeV and 150 MeV

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9

2009 · Physics · Nuclear and Particle Physics · Elementary Particles and Symmetries

Physics (PH) 2009

In the quark model which one of the following represents a proton ?

A

\(udd \)

B

\(uud \)

C

\(u\bar{b} \)

D

\(c\bar{c} \)

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10

2010 · Physics · Nuclear and Particle Physics · Elementary Particles and Symmetries

Physics (PH) 2010

Match the reactions on the left with the associated interactions on the right.

A

(1) \(\pi^+ \rightarrow \mu^+ + \nu_\mu\) (i) Strong

B

(2) \(\pi^0 \rightarrow \gamma + \gamma\) (ii) Electromagnetic

C

(3) \(\pi^0 + n \rightarrow \pi^- + p\) (iii) Weak

D

(1, iii), (2, ii), (3, i)

E

(1, i), (2, ii), (3, iii)

F

(1, ii), (2, i), (3, iii)

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11

2010 · Physics · Nuclear and Particle Physics · Elementary Particles and Symmetries

Physics (PH) 2010

The quark content of \( \Sigma^+ \), \( K^- \), \( \pi^- \) and \( p \) is indicated:
\( \{ \Sigma^+ \} = \{ uus \} \), \( \{ K^- \} = \{ s\bar{u} \} \), \( \{ \pi^- \} = \{ \bar{u}d \} \), \( \{ p \} = \{ uud \} \).
In the process, \( \pi^- + p \rightarrow K^- + \Sigma^+ \), considering strong interactions only, which of the following statements is true?

A

The process is allowed because \(\Delta S = 0 \)

B

The process is allowed because \(\Delta I_3 = 0 \)

C

The process is not allowed because \(\Delta S \neq 0 \) and \(\Delta I_3 \neq 0 \)

D

The process is not allowed because the baryon number is violated

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12

2011 · Physics · Nuclear and Particle Physics · Elementary Particles and Symmetries

Physics (PH) 2011

The isospin and the strangeness of \(\Omega^-\) baryon are

A

1, -3

B

0, -3

C

1, 3

D

0, 3

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13

2012 · Physics · Nuclear and Particle Physics · Elementary Particles and Symmetries

Physics (PH) 2012

Which one of the following sets corresponds to fundamental particles?

A

proton, electron and neutron

B

proton, electron and photon

C

electron, photon and neutrino

D

quark, electron and meson

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14

2012 · Physics · Nuclear and Particle Physics · Elementary Particles and Symmetries

Physics (PH) 2012

Choose the CORRECT statement from the following.

A

Neutron interacts through electromagnetic interaction

B

Electron does not interact through weak interaction

C

Neutrino interacts through weak and electromagnetic interaction

D

Quark interacts through strong interaction but not through weak interaction

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15

2013 · Physics · Nuclear and Particle Physics · Elementary Particles and Symmetries

Physics (PH) 2013

The isospin (I) and baryon number (B) of the up quark is

A

I=1, B=1

B

I=1, B=1/3

C

I=1/2, B=1

D

I=1/2, B=1/3

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16

2014 · Physics · Nuclear and Particle Physics · Elementary Particles and Symmetries

Physics (PH) 2014

Which one of the following high energy processes is allowed by conservation laws?

A

\(p + \bar{p} \to \Lambda^0 + \Lambda^0\)

B

\(\pi^- + p \to \pi^0 + n\)

C

\(n \to p + e^- + \nu_e\)

D

\(\mu^+ \to e^+ + \gamma\)

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17

2014 · Physics · Nuclear and Particle Physics · Elementary Particles and Symmetries

Physics (PH) 2014

Which one of the following three-quark states (\(qqq\), denoted by \(X\), CANNOT be a possible baryon? The corresponding electric charge is indicated in the superscript.

A

\(X^+\)

B

\(X^+\)

C

\(X^-\)

D

\(X^{--}\)

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18

2014 · Physics · Nuclear and Particle Physics · Elementary Particles and Symmetries

Physics (PH) 2014

Consider the process μ⁺ + μ⁻ → π⁺ + π⁻. The minimum kinetic energy of the muons (μ) in the centre of mass frame required to produce the pion (π) pairs at rest is _________ MeV. (Given: m_μ = 105 MeV/c², m_π = 140 MeV/c²)

Check answer

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19

2015 · Physics · Nuclear and Particle Physics · Elementary Particles and Symmetries

Physics (PH) 2015

The decay \( \mu^+ \rightarrow e^+ + \gamma \) is forbidden, because it violates

A

momentum and lepton number conservations

B

baryon and lepton number conservations

C

angular momentum conservation

D

lepton number conservation

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20

2016 · Physics · Nuclear and Particle Physics · Elementary Particles and Symmetries

Physics (PH) 2016

In the SU(3) quark model, the triplet of mesons \((\pi^-, \pi^0, \pi^+)\) has

A

Isospin = 0, Strangeness = 0

B

Isospin = 1, Strangeness = 0

C

Isospin = 1/2, Strangeness = +1

D

Isospin = 1/2, Strangeness = -1

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