A student has made the circuit given below: The student then added a diode. Describe what effect this will have.

Diode is a device that allows current to flow in a particular direction only. It is used for stopping the current from flowing in the wrong direction. It is a semiconductor device that acts as one-way switch for the current. It allows the current to flow easily in one direction but restricts the current from flowing in the opposite direction. So, when the student will add a diode to the given circuit, then the current will flow in one direction only. If the diode is forward biased then it will offer zero resistance, which will allow the current to flow through it whereas if the diode is reverse biased then it will offer infinite resistance, which will stop the current from flowing.

Some students did an experiment to find the best combination of fruits and metals for a cell. The table given below show their results: Meta used Fruit or Veg used Apple Orange Lime Tomato Potato Zinc and iron 0 . 25 0 . 20 0 . 28 0 . 30 0 . 22 Iron and copper 0 . 42 0 . 36 0 . 96 0 . 32 0 . 32 Copper and zinc 0 . 72 0 . 74 0 . 68 0 . 70 0 . 62 State two things the students would need to keep the same to make this a fair test.

The two things that the students would need to keep the same to make this a fair test are conducting material and concentration. The conductors or conducting materials are the material that allows the flow of charge in one or more directions. Conductivity increases with the increase in concentration.

Some students did an experiment to find the best combination of fruits and metals for a cell. The table given below show their results: Meta used Fruit or Veg used Apple Orange Lime Tomato Potato Zinc and iron 0 . 25 0 . 20 0 . 28 0 . 30 0 . 22 Iron and copper 0 . 42 0 . 36 0 . 96 0 . 32 0 . 32 Copper and zinc 0 . 72 0 . 74 0 . 68 0 . 70 0 . 62 The voltage for iron and copper with lime seems too high. Suggest what the students might have done wrong.

Generally, the voltage is highest when we use copper and zinc. When we take copper and zinc with lemon then in this case the electron will flow out from copper into the zinc through the acidic juice inside the lemon. The voltage for iron and copper with lime seems too high in the given table, the student might have made a wrong entry. He might have used zinc wires.

Some students did an experiment to find the best combination of fruits and metals for a cell. The table given below show their results: Meta used Fruit or Veg used Apple Orange Lime Tomato Potato Zinc and iron 0 . 25 0 . 20 0 . 28 0 . 30 0 . 22 Iron and copper 0 . 42 0 . 36 0 . 96 0 . 32 0 . 32 Copper and zinc 0 . 72 0 . 74 0 . 68 0 . 70 0 . 62 Which combination gives the highest voltage?

The combination of zinc and copper gives the highest voltage. When we make a fruit cell we need two different metals and a citric fruit like lemon or orange. If the two metals taken are copper and zinc then in this case the electron will flow out from copper into the zinc through the acidic juice inside the fruit.

Some students did an experiment to find the best combination of fruits and metals for a cell. The table given below show their results: Meta used Fruit or Veg used Apple Orange Lime Tomato Potato Zinc and iron 0 . 25 0 . 20 0 . 28 0 . 30 0 . 22 Iron and copper 0 . 42 0 . 36 0 . 96 0 . 32 0 . 32 Copper and zinc 0 . 72 0 . 74 0 . 68 0 . 70 0 . 62 The students want to light a 1 . 5 volt lamp using fruit cells. Suggest how they might do this.

The students want to light a 1 . 5 volt lamp using fruit cells, so they should use copper and zinc with orange and lime. If we make a fruit cell using copper and zinc then the electrons will flow out from copper into the zinc through the acidic juice inside the orange and lime.

Lucy Hawkins, Fran Eardley, Stuart Lloyd and, Gemma Young Solutions for Chapter: Electrostatics and Electric Currents, Exercise 21: End of Chapter Review

Author:Lucy Hawkins, Fran Eardley, Stuart Lloyd & Gemma Young

Lucy Hawkins Science Solutions for Exercise - Lucy Hawkins, Fran Eardley, Stuart Lloyd and, Gemma Young Solutions for Chapter: Electrostatics and Electric Currents, Exercise 21: End of Chapter Review

Attempt the free practice questions on Chapter 9: Electrostatics and Electric Currents, Exercise 21: End of Chapter Review with hints and solutions to strengthen your understanding. Cambridge Lower Secondary Science Stage 9: Student's Book solutions are prepared by Experienced Embibe Experts.

Questions from Lucy Hawkins, Fran Eardley, Stuart Lloyd and, Gemma Young Solutions for Chapter: Electrostatics and Electric Currents, Exercise 21: End of Chapter Review with Hints & Solutions

EASY

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Student's Book>Chapter 9 - Electrostatics and Electric Currents>End of Chapter Review>Q 10

A student has made this circuit.

Question Image

Describe and explain what will happen if the student changes the variable resistor so that the current has less wire to flow through.

EASY

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Student's Book>Chapter 9 - Electrostatics and Electric Currents>End of Chapter Review>Q 10

A student has made the circuit given below:

Question Image

The student then added a diode. Describe what effect this will have.

EASY

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Student's Book>Chapter 9 - Electrostatics and Electric Currents>End of Chapter Review>Q 11

A teacher is showing her class how static electricity works. She has an acetate rod which she knows will become positively charged when rubbed with the cloth, and a polythene rod that will become negatively charged. She has some unlabelled rods which she thinks become charged, but she doesn't know which way. Describe the experiment she can do to:
Investigate whether they become positively charged or negatively charged.

EASY

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Student's Book>Chapter 9 - Electrostatics and Electric Currents>End of Chapter Review>Q 12

Some students did an experiment to find the best combination of fruits and metals for a cell.

The table given below show their results:

Meta used	Fruit or veg used
Meta used	Apple	Orange	Lime	Tomato	Potato
Zinc and iron	$0.25$	$0.20$	$0.28$	$0.30$	$0.22$
Iron and copper	$0.42$	$0.36$	$0.96$	$0.32$	$0.32$
Copper and zinc	$0.72$	$0.74$	$0.68$	$0.70$	$0.62$

The students forgot to write down the units for these results. What should the units be?

EASY

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Student's Book>Chapter 9 - Electrostatics and Electric Currents>End of Chapter Review>Q 12

Some students did an experiment to find the best combination of fruits and metals for a cell.

The table given below show their results:

Meta used	Fruit or Veg used
Meta used	Apple	Orange	Lime	Tomato	Potato
Zinc and iron	$0.25$	$0.20$	$0.28$	$0.30$	$0.22$
Iron and copper	$0.42$	$0.36$	$0.96$	$0.32$	$0.32$
Copper and zinc	$0.72$	$0.74$	$0.68$	$0.70$	$0.62$

State two things the students would need to keep the same to make this a fair test.

EASY

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Student's Book>Chapter 9 - Electrostatics and Electric Currents>End of Chapter Review>Q 12

Some students did an experiment to find the best combination of fruits and metals for a cell.

The table given below show their results:

Meta used	Fruit or Veg used
Meta used	Apple	Orange	Lime	Tomato	Potato
Zinc and iron	$0.25$	$0.20$	$0.28$	$0.30$	$0.22$
Iron and copper	$0.42$	$0.36$	$0.96$	$0.32$	$0.32$
Copper and zinc	$0.72$	$0.74$	$0.68$	$0.70$	$0.62$

The voltage for iron and copper with lime seems too high. Suggest what the students might have done wrong.

EASY

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Student's Book>Chapter 9 - Electrostatics and Electric Currents>End of Chapter Review>Q 12

Some students did an experiment to find the best combination of fruits and metals for a cell.

The table given below show their results:

Meta used	Fruit or Veg used
Meta used	Apple	Orange	Lime	Tomato	Potato
Zinc and iron	$0.25$	$0.20$	$0.28$	$0.30$	$0.22$
Iron and copper	$0.42$	$0.36$	$0.96$	$0.32$	$0.32$
Copper and zinc	$0.72$	$0.74$	$0.68$	$0.70$	$0.62$

Which combination gives the highest voltage?

EASY

Lower Secondary Stage 9

IMPORTANT

Cambridge Lower Secondary Science Stage 9: Student's Book>Chapter 9 - Electrostatics and Electric Currents>End of Chapter Review>Q 12

Some students did an experiment to find the best combination of fruits and metals for a cell.

The table given below show their results:

Meta used	Fruit or Veg used
Meta used	Apple	Orange	Lime	Tomato	Potato
Zinc and iron	$0.25$	$0.20$	$0.28$	$0.30$	$0.22$
Iron and copper	$0.42$	$0.36$	$0.96$	$0.32$	$0.32$
Copper and zinc	$0.72$	$0.74$	$0.68$	$0.70$	$0.62$

The students want to light a $1.5 volt$ lamp using fruit cells. Suggest how they might do this.

Lucy Hawkins, Fran Eardley, Stuart Lloyd and, Gemma Young Solutions for Chapter: Electrostatics and Electric Currents, Exercise 21: End of Chapter Review

Lucy Hawkins Science Solutions for Exercise - Lucy Hawkins, Fran Eardley, Stuart Lloyd and, Gemma Young Solutions for Chapter: Electrostatics and Electric Currents, Exercise 21: End of Chapter Review

Questions from Lucy Hawkins, Fran Eardley, Stuart Lloyd and, Gemma Young Solutions for Chapter: Electrostatics and Electric Currents, Exercise 21: End of Chapter Review with Hints & Solutions

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