Question(a)

Fig. 6.1 shows a copper wire connected to a battery and placed between the poles of a strong magnet.

(i) Describe two ways to change the apparatus so that the wire moves downwards when the switch is closed.

To make the wire move downwards when the switch is closed, you can:

1. Reverse the polarity of the battery, which will reverse the direction of the current flowing through the wire.
2. Reverse the polarity of the magnet, which will change the direction of the magnetic field.

▶️Answer/Explanation

Answer:

1. Reverse the battery polarity / current.
2. Reverse the magnet polarity.

Explanation: The direction of the force on the wire depends on the direction of the current and the magnetic field. By reversing either the current or the magnetic field, the force will act in the opposite direction, causing the wire to move downwards.

(Subtopic – P4.2.2)
(ii) State the term that describes a flow of electrons in a metal conductor.

The term that describes the flow of electrons in a metal conductor is “current.”

▶️Answer/Explanation

Answer: Current Explanation: In a metal conductor, the flow of electrons constitutes an electric current. The direction of conventional current is opposite to the direction of electron flow.

Question(b)

A β-particle is an electron. α-particles and β-particles are radioactive emissions released during the radioactive decay of isotopes.

(i) State the meaning of the terms:

1. Radioactive decay: The process by which an unstable atomic nucleus loses energy by emitting radiation, such as α-particles or β-particles.

2. Isotopes: Atoms of the same element that have the same number of protons but different numbers of neutrons, resulting in different atomic masses.

▶️Answer/Explanation

Answer:

1. Radioactive decay is the process by which an unstable nucleus loses energy by emitting radiation.
2. Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons.

Explanation: Radioactive decay is a spontaneous process that occurs in unstable nuclei, leading to the emission of particles or energy. Isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons, which affects their stability and radioactive properties.

(Subtopic – P5.2.2)
(ii) Complete the sentences below using the symbols α and β.

β particles are less ionising than α particles.

α particles are less penetrating than β particles.

▶️Answer/Explanation

Answer:

β particles are less ionising than α particles.

α particles are less penetrating than β particles.

Explanation: α-particles are helium nuclei and are highly ionising but have low penetration power due to their large mass and charge. β-particles are electrons or positrons and are less ionising but more penetrating than α-particles.

Question(c)

A plastic ruler and a piece of cloth are both uncharged. A student rubs the plastic ruler with the cloth. The plastic ruler becomes positively charged.

(i) Describe in terms of electrons how the plastic ruler becomes positively charged.

When the plastic ruler is rubbed with the cloth, electrons are transferred from the ruler to the cloth. This leaves the ruler with a deficiency of electrons, resulting in a positive charge.

▶️Answer/Explanation

Answer: The ruler loses electrons.
Explanation: When two materials are rubbed together, electrons can be transferred from one material to another. In this case, electrons are transferred from the plastic ruler to the cloth, leaving the ruler with a positive charge due to the loss of electrons.

(Subtopic – P4.2.1)
(ii) State which row from Table 6.1 shows the charge on the cloth compared to the charge on the plastic ruler.

Row 4 shows the charge on the cloth compared to the charge on the plastic ruler. The cloth has a negative charge equal in magnitude to the positive charge on the ruler.

▶️Answer/Explanation

Answer: Row 4
Explanation: Since the ruler loses electrons and becomes positively charged, the cloth gains those electrons and becomes negatively charged. The charges are equal in magnitude but opposite in sign, which corresponds to row 4 in Table 6.1.