{"id":3,"date":"2014-11-12T09:28:07","date_gmt":"2014-11-12T09:28:07","guid":{"rendered":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsecphyshu2hwrk\/homework\/"},"modified":"2019-10-22T15:20:26","modified_gmt":"2019-10-22T15:20:26","slug":"homework","status":"publish","type":"page","link":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsecphyshu2hwrk\/homework\/","title":{"rendered":"Exercise 2_1"},"content":{"rendered":"

Unit 2\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Particles and Waves<\/strong><\/p>\n

Homework 2.1\u00a0<\/strong><\/p>\n

1. The following strong interaction has been observed.<\/p>\n

K\u2212<\/sup> + p \u2192 n + X<\/strong><\/p>\n

The K\u2212<\/sup> is a strange meson of quark composition \u016b s.<\/p>\n

The u quark has a charge of +2\/3.<\/p>\n

The d quark has a charge of \u22121\/3.<\/p>\n

(a)\u00a0\u00a0 Determine the charge of the strange quark.
\n(b)\u00a0\u00a0 Use the appropriate conservation law to determine whether particle X is positive, negative or neutral.
\n(c)\u00a0\u00a0 State whether particle X is a baryon or a meson.\u00a0 Justify your answer.<\/p>\n

2.\u00a0 \u00a0 (a)\u00a0\u00a0 The equation for a \u03b2\u2212<\/sup> decay can be written as:<\/p>\n

\"\"<\/a><\/p>\n

(i)\u00a0 For each of these four particles, state its name, and where appropriate, its quark composition.
\n(ii)\u00a0 State the interaction associated with \u03b2\u00a0decay.<\/p>\n

(b)\u00a0\u00a0 In 1995 scientists at CERN created atoms of antihydrogen.
\n(i)\u00a0 Name the particles that make up an atom of antihydrogen.
\n(ii)\u00a0 State the charge of an atom of antihydrogen.
\n(iii)\u00a0 Explain why it is not possible to store atoms of antihydrogen.<\/p>\n

3.\u00a0\u00a0\u00a0 The apparatus shown in the diagram is designed to accelerate alpha particles.<\/p>\n

\"\"<\/a><\/p>\n

An alpha particle travelling at a speed of 2\u00b760\u00a0\u00d7\u00a0106<\/sup>\u00a0m\u00a0s\u22121<\/sup>\u00a0passes through a hole in plate A.\u00a0 The mass of an alpha particle is 6\u00b764\u00a0\u00d7\u00a010\u221227<\/sup>\u00a0kg and its charge is 3\u00b720\u00a0\u00d7\u00a010\u221219<\/sup>\u00a0C.<\/p>\n

(a)\u00a0\u00a0 When the alpha particle reaches plate B, its kinetic energy has increased to 3\u00b705\u00a0\u00d7\u00a010\u221214<\/sup>\u00a0J.
\nShow that the work done on the alpha particle as it moves from plate A to plate B is 8.1\u00a0\u00d7\u00a010\u221215<\/sup>\u00a0J,
\n(b)\u00a0\u00a0 Calculate the potential difference between plates A and B.
\n(c)\u00a0\u00a0 The apparatus is now adapted to accelerate\u00a0electrons<\/strong>\u00a0from A to B through the same potential difference.
\nHow does the increase in kinetic energy of an electron compare with the increase in kinetic energy of the alpha particle in part (a)?\u00a0 Justify your answer.<\/p>\n

4.\u00a0\u00a0\u00a0 Identification of elements in a semiconductor sample can be carried out using an electron scanner to release atoms from the surface of the sample for analysis.\u00a0 Electrons are accelerated from rest between a cathode and anode by a potential difference of 2\u00b740\u00a0kV.<\/p>\n

A variable voltage supply connected to the deflection plates enables the beam to scan the sample between points A and B shown in the figure below.<\/p>\n

\"\"<\/a><\/p>\n

(a)\u00a0\u00a0 Calculate the speed of the electrons as they pass through the anode.<\/p>\n

(b)\u00a0\u00a0 Explain why the electron beam follows:
\n(i)\u00a0 a curved path between the plates;
\n(ii)\u00a0 a straight path beyond the plates.
\n(c)\u00a0\u00a0 The anode voltage is now increased.\u00a0 State what happens to the length of the sample scanned by the electron beam.\u00a0 You must justify your answer.<\/p>\n

5.\u00a0\u00a0\u00a0 A cyclotron is a particle accelerator which consists of two D-shaped hollow structures, called \u201cdees\u201d, placed in a vacuum.<\/p>\n

\"\"<\/a><\/p>\n

The diagram below shows the cyclotron viewed from above.<\/p>\n

\"\"<\/a><\/p>\n

(a)\u00a0\u00a0 Protons are released from rest at point A and accelerated across the gap between the \u201cdees\u201d by a voltage of 2\u00b700\u00a0kV.
\nShow that the speed of the protons as they\u00a0first\u00a0<\/strong>reach the right hand \u201cdee\u201d is 6\u00b719\u00a0\u00d7\u00a0105<\/sup>\u00a0m\u00a0s\u22121<\/sup>.
\n(b)\u00a0\u00a0 Inside the \u201cdees\u201d the electric field strength is zero but there is a uniform magnetic field.\u00a0 This forces the protons to move in semi-circular paths when inside the \u201cdees\u201d.
\nState the direction of the magnetic field in the \u201cdees\u201d.
\n(c)\u00a0\u00a0 While the protons are inside the \u201cdee\u201d, the polarity of the applied voltage is reversed so that the protons are again accelerated when they cross to the left hand \u201cdee\u201d.
\nCalculate the speed of the protons as they\u00a0first<\/strong>\u00a0enter the left hand \u201cdee\u201d.<\/p>\n

6.<\/p>\n

\"\"<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Unit 2\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Particles and Waves Homework 2.1\u00a0 1. The following strong interaction has been observed. K\u2212 + p \u2192 n + X The K\u2212 is a strange meson of quark composition \u016b s. The u quark has a charge of +2\/3. The d quark has a charge of \u22121\/3. (a)\u00a0\u00a0 Determine the charge of the … Continue reading Exercise 2_1<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":2454,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"open","ping_status":"open","template":"","meta":{"footnotes":""},"class_list":["post-3","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsecphyshu2hwrk\/wp-json\/wp\/v2\/pages\/3","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsecphyshu2hwrk\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsecphyshu2hwrk\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsecphyshu2hwrk\/wp-json\/wp\/v2\/users\/2454"}],"replies":[{"embeddable":true,"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsecphyshu2hwrk\/wp-json\/wp\/v2\/comments?post=3"}],"version-history":[{"count":34,"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsecphyshu2hwrk\/wp-json\/wp\/v2\/pages\/3\/revisions"}],"predecessor-version":[{"id":158,"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsecphyshu2hwrk\/wp-json\/wp\/v2\/pages\/3\/revisions\/158"}],"wp:attachment":[{"href":"https:\/\/blogs.glowscotland.org.uk\/gc\/hyndsecphyshu2hwrk\/wp-json\/wp\/v2\/media?parent=3"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}