Questions

Q1.

A battery sends a current through a metal wire.

(a) (i) Complete the sentence by putting a cross ( ) in the box next to your answer.

Direct current is movement of charge

(1)

A backwards and forwards

B in many directions

C in one direction

D up and down

(ii) Complete the sentence by putting a cross ( ) in the box next to your answer.

The particles that flow in the metal wire are

(1)

A atoms

B electrons

C protons

D neutrons

(b) The current in a wire is 3.7 A.

Calculate the charge that flows into the wire in 13 s.

(2)

charge = . . . . . . . . . . . . . . . . . . . . . . C

(c) Plastic is an insulator.

A student rubs a piece of plastic with a cloth.

This gives the plastic a negative charge.

(i) Explain how the plastic is charged by the rubbing.

(2)

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(ii) The cloth is also charged when it rubs against the plastic.

Describe the charge on the cloth.

(2)

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(Total for Question is 8 marks)

Q2. Waste gases contain smoke particles.

The diagram shows how smoke particles can be removed from waste gases as they rise througha chimney.

When the smoke particles go through the metal grid they become negatively charged.

There is a current of 1.4 A between the grid and the plates.

(i) Calculate the charge transferred by this current in two minutes. State the unit.

(3)

charge = ........................................ unit ........................................

(ii) The potential difference between the grid and the plate is 400 V.

Calculate the electrical energy transferred in two minutes.

(2)

energy transferred = ....................................... joules

Q3.

A student is investigating a filament lamp.

(a) (i) Complete the sentence by putting a cross ( ) in the box next to your answer.

The current in the filament lamp is a flow of

(1)

A protons

B neutrons

C electrons

D atoms

(ii) The student uses this circuit in his investigation.

State what is measured by the meters.

(2)

Meter 1 measures.............................................................................................................................................

Meter 2 measures.............................................................................................................................................

(b) The normal operating potential difference (voltage) and current of the filament lamp is 6 V,0.4 A.

Calculate the energy supplied to the lamp under these conditions in 20 s.

(2)

energy = ........................................................... J

(c) The graph shows how current varies with potential difference (voltage) for another filamentlamp.

Calculate the resistance of the lamp when the current in the lamp is 0.3 A.

resistance = potential difference ÷ current (R = V / I)

(3)

resistance = ........................................................... Ω

(Total for Question = 8 marks)

Q4. Electrostatic discharge

(a) Marie works in an office which has a nylon carpet.

She walks across the carpet towards her filing cabinet.

There is friction between her shoes and the carpet.

When she touches the metal handle of her filing cabinet she feels an electric shock.

(i) State the name of the charged particles which have been transferred between the carpetand her shoes.

(1)

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(ii) The following sentences explain how Marie got the electric shock.

The sentences are in the wrong order.

Put them in the correct order by numbering the boxes.

Two have been done for you.

(2)

actions order in which the actions happenMarie walks across the nylon carpet 1charge flows from Marie to the filing cabinetMarie touches the handle 4charge is transferred by friction on to MarieMarie has lost her negative chargea negative charge builds up on Marie

(b) Marie has another filing cabinet which has a black conductive strip at the top.

This black strip helps to prevent electric shocks.

This strip has a high resistance but still conducts charge.

If Marie touches the strip before touching the handle she does not feel a shock.

Explain, using the idea of electric current, why Marie does not feel a shock.

(3)

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*(c) Sparks from electrostatic discharge can sometimes be very dangerous. They can cause afire or an explosion.

Safety precautions are taken to reduce risks.

Explain how safety precautions, in a particular situation, reduce the risks of fire or explosion.

You may draw a labelled diagram to help with your answer.

(6)

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Q5.

An electrostatic air filter is designed to remove dust particles from the air in a room.

A fan blows dusty air past several metal rods and metal plates.

There is a large potential difference (voltage) between the metal rods and the metal plates.

(a) Complete the sentence by putting a cross ( ) in the box next to your answer.

When dusty air goes past the metal rods, the dust particles become negatively charged.

This is because the dust particles

(1)

A lose electrons

B lose protons

C gain electrons

D gain protons

(b) When the dusty air flows past the metal plates, the dust particles settle on the metal plates.

Explain why the dust particles settle on the metal plates.

(2)

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(c) (i) State what happens to the charge on the dust particles when they settle on the metalplates.

(1)

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(ii) Explain why the charge does not build up on the metal plates.

(2)

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(d) There is a current of 1.2 mA in the circuit.

Calculate the charge transferred by this current in 40 s.

State the unit.

(3)

charge transferred = ........................................................... unit:...........................................................

Q6.

A lightning strike on a metal tower can be described as follows.

In the cloud.

A thunder cloud contains moving ice particles.

Some of these ice particles are negatively charged and some are positively charged.

The negatively charged particles move to the bottom of the cloud.

When the charged cloud is over the metal tower.

A charge builds up on the top of the metal tower as the cloud passes over.

During the lightning flash.

Eventually a flash of lightning travels between the cloud and the tower.

(i) Which row of this table is correct when the cloud is over the top of the tower before thelightning flash?

Put a cross ( ) in the box next to your answer.

(1)

charge on top of the cloudis

charge on top of thetower is

A negative negative B negative positive C positive positive D positive negative

(ii) Here are fourstatements. Threeof these are a reason for what happens at each stage.

Choose the best reason for each of the stages listed below by writing its number in the box next to the description of what happens. One has been done for you. A reason can only be used once.

(2)

(iii) Explain what happens to the charge on the metal tower as a result of the lightningflash.

(2)

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Q7.

A student wins a trophy. It is a metal cup on a black plastic base.

The student cleans the trophy.She holds one of the metal handles and rubs the rest of the trophy with a dry cloth.

(i) Complete the sentence by putting a cross ( ) in the box next to your answer.

The plastic base becomes negatively charged because it gains

(1)

A atoms

B becquerel

C einstein

D radium

(ii) Explain why the base gains a negative charge when she rubs the trophy with thecloth.

(2)

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(iii) The metal cup does not become charged when she rubs the trophy. Suggest why the cup does not become charged.

(2)

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(iv) Some dust particles in the air drift near to the plastic base just after she cleans thetrophy.

Which diagram shows the correct distribution of charges on a dust particle near to thecharged plastic base?

Put a cross ( ) in the box next to your answer.

(1)

Mark Scheme

Q1.

Answer Acceptable answers Mark(a)(i) C (1)(a)(ii) B (1)

(b) substitution (1)3.7 x 13evaluation (1)48 (C)

48.1Correct answer with nocalculation scores 2 marks

(2)

(c)(i) Correct responses can be seen in (i) or(ii)An explanation linking

electrons (1)

and one of

removed by friction (1)

(transferred) to plastic (1)

["positive electrons/ protons moving",seen anywhere in part (i) or (ii) losesthis mark]

ignore reference to charge beforerubbing

transferred from cloth

(2)

(c)(ii) opposite to charge on plastic (1)

equal to charge on the plastic (1)

charge on cloth is positive

same size as charge on plastic

(2)

electrons transferred from the clothequal to electrons lost by cloth

Total question = 8 marks

Q2.

QuestionNumber

Answer Acceptable answers Mark

(i) substitution (1)

1.4 × 60 × 2

evaluation (1)

= 168

unit (1)

coulombs / C

give full marks forcorrect answer with

correct unit, noworking

(3)

QuestionNumber

Answer Acceptable answers Mark

(ii) substitution (1)

1.4 × 400 × 60 × 2

evaluation(1)

67 200 (J)

give full marks forcorrect answer, no

working

(2)

Q3.

Q4.

QuestionNumber

Answer Acceptable answers Mark

(a)(i) electrons (1)

QuestionNumber

Answer Acceptable answers Mark

(a)(ii) • row 4 and 6labelled 2,3 (1)

• row 2 and 5labelled 5,6 (1)

(2)

QuestionNumber

Answer Acceptable answers Mark

(b) An explanation linkingthree of the following

• charge flows fromMarie through the

(3)

conductive strip (1)

• this constitutes anelectric current (1)

• the (relatively) highresistance of the strip

means that the currentis (relatively) small (1)

• compared with the(larger) current which

would flow through themetal handle (1)

• idea of earthing (1)

• Marie no longercharged when she

touches the handle (1)

QuestionNumber

Indicative content Mark

QWC *(c) An explanation linkingsome of the following

points

• a clear statementof the situation being

considered

• an explanation ofhow the electrostaticcharge would build upif no safety precaution

was taken

• an explanation ofwhy a spark is

generated

• a statement aboutthe consequences ofthis spark resulting in

the ignition of the{combustible /

flammable} source

• detail of the safetyprecaution

• an explanation ofelectrostatic processes

with the safetyprecaution in place.

(6)

• a statement thatthe previously

identified risk is nowreduced

Level 0 No rewardable material1 1-2 • a simple explanation or a diagram of a

potentially dangerous situation with either astatement of a possible consequence or a

relevant safety precaution

• the student uses everyday language andthe response lacks clarity and organisation

• spelling, punctuation and the rules ofgrammar are used with limited accuracy

2 3-4

• some explanation or a partially labelleddiagram of the situation and some explanation

of how the charge would build up in theunprotected situation linked to a relevant

safety precaution or an explanation of how thisresults in a controlled discharge or prevents

the charge separation in the first place

• the student uses some technical terms andshows some clarity and organisation

• spelling, punctuation and the rules ofgrammar are used with some accuracy

3 5 - 6 • a detailed explanation or a fully labelleddiagram of the situation and explanation of

how the charge would build up in theunprotected situation clearly linked to a

relevant safety precaution and explanation ofhow this results in a controlled discharge orprevents the charge separation in the first

place

• the student uses a range of technical termsand shows good clarity and organisation

• spelling, punctuation and the rules ofgrammar are used with considerable accuracy

Q5.

Q6.

Answer Acceptable answers MarkC (1)

(ii) In the cloud : reason 3 (1)

At the tower: reason 2

(2)

(1)(iii) An explanation linking

the charge was neutralised (1)by a transfer/flow of electrons (1)

Discharged/ becomes zero

gained electrons / negative charge

(2)

Q7.

Answer Acceptable answers Mark(i) B electrons (1)(ii) An explanation linking

(negative) electrons transfer (1)

because of friction/from cloth (to base) (1)

negative charge (reject protons andpositive charge for this mp) moves

cloth loses {electrons/negativecharge} (to base) = 2

(2)

(iii) A suggestion to include

charge (any) could move through cup/metal (1)

(cup is) earthed (1)

cup/metal is a conductor ignore metalis not an insulator

to {earth/ ground} / {to/ through}student's hand

(2)

(iv)

(1)

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