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Physical Scienc... NATIONAL SENIOR CERTIFICATE: PHYSICAL SCIENCES: PAPER I Page 11 of 12 QUESTION 8 ELECTRODYNAMICS 8.1 A conductor is hanging from the ceiling on two springs in an external magnetic field. The springs and the conductor are shown in the diagram. A conventional current is directed from left to right through the conductor. 8.1.1 In which direction must an external magnetic field be directed to increase the tension in the springs supporting the conductor? 8.1.2 Name two factors you could adjust to increase the tension in the springs. 8.2 An iron-core transformer is illustrated below. [Source: <http://www.school-for-champions.com/science/images/ac_transformers_simple.gif>] 8.2.1 State Faraday's Law of electromagnetic induction. 8.2.2 Explain the operation of an iron-core transformer. Use bullet points in your answer. Eskom produces electricity at a power station with a potential difference of 20 kV . This electricity is transmitted via a network of cables across the country at a potential difference of 765 kV . 8.2.3 Why does Eskom transmit energy at such a high voltage? Use a suitable equation to help you explain your answer. 8.2.4 Calculate the ratio of the number of turns on the secondary coil to the number of turns on the primary coil needed to change 20 kV to 765 kV 8.2.5 Name the type of transformer used to change 20 kV to 765 kV . \( [19] \) IEB Copyright (C) 2016 PLEASE TURN OVER NATIONAL SENIOR CERTIFICATE: PHYSICAL SCIENCES: PAPER I Page 12 of 12 QUESTION 9 PHOTONS AND ELECTRONS The work functions of selected metals are recorded in the table below. \begin{tabular}{|c|c|} \hline Metal & Work Function \( \left(\times \mathbf{1 0}^{-19} \mathbf{~ J}\right) \) \\ \hline Sodium & 3,94 \\ \hline Aluminium & 6,53 \\ \hline Zinc & 6,90 \\ \hline Iron & 7,20 \\ \hline \end{tabular} 9.1 Define work function. Light of wavelength 296 nm is incident on a sample of each metal in turn. 9.2 Calculate the energy of a photon of light of 296 nm . 9.3 Which metals listed in the table will emit electrons at this wavelength? 9.4 Calculate the maximum kinetic energy of the electrons ejected from sodium metal when light of 296 nm is incident on the metal. 9.5 The intensity of the 296 nm light is now increased. Will the light now be able to

          Physical Scienc...
NATIONAL SENIOR CERTIFICATE: PHYSICAL SCIENCES: PAPER I
Page 11 of 12

QUESTION 8 ELECTRODYNAMICS
8.1 A conductor is hanging from the ceiling on two springs in an external magnetic field. The springs and the conductor are shown in the diagram.

A conventional current is directed from left to right through the conductor.
8.1.1 In which direction must an external magnetic field be directed to increase the tension in the springs supporting the conductor?
8.1.2 Name two factors you could adjust to increase the tension in the springs.
8.2 An iron-core transformer is illustrated below.
[Source: <http://www.school-for-champions.com/science/images/ac_transformers_simple.gif>]
8.2.1 State Faraday's Law of electromagnetic induction.
8.2.2 Explain the operation of an iron-core transformer. Use bullet points in your answer.

Eskom produces electricity at a power station with a potential difference of 20 kV . This electricity is transmitted via a network of cables across the country at a potential difference of 765 kV .
8.2.3 Why does Eskom transmit energy at such a high voltage? Use a suitable equation to help you explain your answer.
8.2.4 Calculate the ratio of the number of turns on the secondary coil to the number of turns on the primary coil needed to change 20 kV to 765 kV
8.2.5 Name the type of transformer used to change 20 kV to 765 kV .
\( [19] \)
IEB Copyright (C) 2016
PLEASE TURN OVER
NATIONAL SENIOR CERTIFICATE: PHYSICAL SCIENCES: PAPER I
Page 12 of 12

QUESTION 9
PHOTONS AND ELECTRONS
The work functions of selected metals are recorded in the table below.
\begin{tabular}{|c|c|}
\hline Metal & Work Function \( \left(\times \mathbf{1 0}^{-19} \mathbf{~ J}\right) \) \\
\hline Sodium & 3,94 \\
\hline Aluminium & 6,53 \\
\hline Zinc & 6,90 \\
\hline Iron & 7,20 \\
\hline
\end{tabular}
9.1 Define work function.

Light of wavelength 296 nm is incident on a sample of each metal in turn.
9.2 Calculate the energy of a photon of light of 296 nm .
9.3 Which metals listed in the table will emit electrons at this wavelength?
9.4 Calculate the maximum kinetic energy of the electrons ejected from sodium metal when light of 296 nm is incident on the metal.
9.5 The intensity of the 296 nm light is now increased. Will the light now be able to

Physical Scienc...
NATIONAL SENIOR CERTIFICATE: PHYSICAL SCIENCES: PAPER I
Page 11 of 12

QUESTION 8 ELECTRODYNAMICS
8.1 A conductor is hanging from the ceiling on two springs in an external magnetic field. The springs and the conductor are shown in the diagram.

A conventional current is directed from left to right through the conductor.
8.1.1 In which direction must an external magnetic field be directed to increase the tension in the springs supporting the conductor?
8.1.2 Name two factors you could adjust to increase the tension in the springs.
8.2 An iron-core transformer is illustrated below.
[Source: <http://www.school-for-champions.com/science/images/actransformerssimple.gif>]
8.2.1 State Faraday's Law of electromagnetic induction.
8.2.2 Explain the operation of an iron-core transformer. Use bullet points in your answer.

Eskom produces electricity at a power station with a potential difference of 20 kV . This electricity is transmitted via a network of cables across the country at a potential difference of 765 kV .
8.2.3 Why does Eskom transmit energy at such a high voltage? Use a suitable equation to help you explain your answer.
8.2.4 Calculate the ratio of the number of turns on the secondary coil to the number of turns on the primary coil needed to change 20 kV to 765 kV
8.2.5 Name the type of transformer used to change 20 kV to 765 kV .
[19]
IEB Copyright (C) 2016
PLEASE TURN OVER
NATIONAL SENIOR CERTIFICATE: PHYSICAL SCIENCES: PAPER I
Page 12 of 12

QUESTION 9
PHOTONS AND ELECTRONS
The work functions of selected metals are recorded in the table below.

Metal Work Function (×1 0^-19 𝐉)

Sodium 3,94

Aluminium 6,53

Zinc 6,90

Iron 7,20

9.1 Define work function.

Light of wavelength 296 nm is incident on a sample of each metal in turn.
9.2 Calculate the energy of a photon of light of 296 nm .
9.3 Which metals listed in the table will emit electrons at this wavelength?
9.4 Calculate the maximum kinetic energy of the electrons ejected from sodium metal when light of 296 nm is incident on the metal.
9.5 The intensity of the 296 nm light is now increased. Will the light now be able to

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