Test (Unit 18-21)

46 M

2h30m 80

/GIII :........................................................ Code: 5054 Class: GBIII

:................................................................................................................

heory Section:T [Total arks]

Time Allowed: Maximum Marks:

Date

Name Paper: Physics

1

Adabistan-e-Soophia

[Turn over

On Fig. 1.1, mark the charge on the tree. [1]

Fig. 1.1

Fig..1.1 shows a thunder cloud with a flat, positively charged base. It passes over a tall 1 (a) tree growing in a region of flat, open land.

+ + + + + + + +

(not to scale)

(i)

(ii) Explain how the tree becomes charged.

..................................................................................................................................

..................................................................................................................................

............................................................................................................................. [2]

(iii) A lightning strike occurs and, in 2.0 × 10–4 s, a charge of 560 C passes from the cloud to the tree. The size of the charge on an electron is 1.6 × 10–19 C.

1. Calculate the number of electrons that pass between the tree and the cloud.

number = ................................................. [2]

2

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2. Calculate the average current in the lightning strike.

current = ................................................. [2]

(b) Two flat metal plates are positioned horizontally, one above the other. Fig. 11.2 shows the positive terminal of a high-voltage supply unit connected to the bottom plate and the negative terminal connected to the top plate.

–high-voltagesupply unit

horizontalmetal plates

+

Fig. 11.2

The high-voltage supply is switched on.

(i) On Fig. 11.2, draw the shape and the direction of the electric field produced. [3]

(ii) Suggest why a small, charged oil droplet placed between the two metal plates accelerates upwards.

..................................................................................................................................

..................................................................................................................................

..................................................................................................................................

............................................................................................................................. [3]

(iii) The oil droplet touches the top metal plate. State and explain what happens to the charge on the oil droplet.

..................................................................................................................................

..................................................................................................................................

............................................................................................................................. [2]

3

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Fig. 2.1

Fig. 2.1 is the circuit diagram.

2 A 600 Ω resistor and a thermistor are connected in series with an ammeter and a 20 V d.c. (direct current) power supply. A voltmeter is in parallel with the resistor.

V

A

600

thermistor

20 Vd.c.powersupply

+_

The ammeter reads 0.025 A.

(a) Calculate

(i) the reading on the voltmeter,

reading = ................................................. [2]

(ii) the resistance of the thermistor.

resistance = ................................................. [2]

(b) The temperature of the thermistor increases.

State what, if anything, happens to

(i) the resistance of the thermistor,

............................................................................................................................. [1]

(ii) the ammeter reading and to the voltmeter reading.

ammeter reading: .....................................................................................................

voltmeter reading: .....................................................................................................[1]

4

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[1]

current = .................................................. [3]

Three cells identical to the cell in Fig. 3.1 make up a 4.5 V battery. The battery is

........ [1]

Fig. 3.1

Fig. 3.1 shows a cell.3

(a) What does the 1.5 V indicate about the cell?

..............................................................................................................................

(b) connected in series with a 180 Ω resistor.

Calculate the current in the circuit.

(c) A second 180 Ω resistor is connected in parallel with the 180 Ω resistor from (b).

(i) In the space below, draw the circuit diagram of the two resistors in parallel, connected to the battery. Use standard symbols.

(ii) State the value of

1. the potential difference across the second 180 Ω resistor, ...................................

2. the current in the second 180 Ω resistor. ..............................................................[2]

[Turn over

5

Fig. 4.1

In the circuit of Fig. 4.1, a 12 V car battery is connected to three identical lamps and two 4 switches. The resistance of the battery is so small that it may be ignored.

L2

L1

12 V

L3 S2

S1

(a) (i) When switches S1 and S2 are both open, which two lamps are in series?

............................................................. and ..............................................................

(ii) When switches S1 and S2 are both closed, which two lamps are in parallel?

............................................................. and ..............................................................[2]

(b) Each of the three lamps glows with full brightness when there is a p.d. of 12 V across the lamp.

With a smaller p.d., a lamp will glow with partial brightness.

With no p.d. across it, it will be off.

Complete the tables below, to show how the lamps glow with different switch combinations. Tick one box in each row.

switch combination: S1 closed and S2 open

fullbrightness

partialbrightness

off

L1

L2

L3[2]

switch combination: S1 open and S2 closed

fullbrightness

partialbrightness

off

L1

L2

L3[2]

6

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Fig. 5.1

in the circuit of Fig. 5.1.5 A student has two wires A and B. She connects each in turn between the terminals P and Q

meter 1

meter 2

P

wire Aor wire B

Q

For each wire, she measures the current in the wire when there are various potential differences across it.

(a) (i) Which of the two meters measures the current? ......................................................

(ii) Name this type of meter. ..........................................................................................

(b) (i) Which of the two meters measures the potential difference (p.d.)? .........................

(ii) Name this type of meter. ..........................................................................................[2]

Fig. 5.2

the lines shown in Fig. 5.2. (c) When the student draws the graphs of p.d. against current for the two wires, she gets

00

1

2wire A

wire B

3

4

0.2 0.4 0.6 0.8

p.d. /V

current / A

7

From Fig. 5.2, find the p.d. across wire A when there is a current of 0.8 A in it. (i)

p.d. = ...............................................V [1]

(ii) Calculate the resistance of wire A when the current in it is 0.8 A.

resistance = ................................................. [4]

(iii) From Fig. 8.2, how can you tell that the resistance of wire A remains constant during the experiment?

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [1]

(iv) How can you tell that the resistance of wire B is greater than the resistance of wire A?

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [1]

(v) Wires A and B are made of the same material and have the same thickness.

State, giving your reasons, which of the wires is the longer wire.

..................................................................................................................................

..................................................................................................................................

.............................................................................................................................. [1]

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[Total 18 Marks]

8

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ATP Section:

Fig. 1.1

A student connects the circuit shown in Fig. 1.1.

1 (a) A student connects a cell, a switch and three resistors to make a circuit. The resistors are labelled A, B and C.

Resistors A and B, the cell and the switch are all in series. Resistor C is in parallel with the cell.

(i) In the space below, draw the circuit diagram.

[2]

(ii) On your circuit diagram, draw the symbol for a voltmeter, connected to measure the voltage across resistor A. [1]

(b) X, Y and Z are three identical lamps.

ZX

Y

The student closes the switch. Lamp Z lights dimly. Lamp X and lamp Y do not light.

Tick TWO of the following which are possible explanations.

both lamp X and lamp Y are faulty

only lamp X is faulty

only lamp Y is faulty

the cell is running down

a connecting lead from the cell is broken

the current in lamp X and in lamp Y is too small

[2]

9

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2 A student investigates the effect of changing the length of a piece of resistance wire in a circuit containing a lamp. The resistance of the lamp is similar to the resistance of a 1 m length of the wire.The circuit is set up as shown in Fig. 2.1.

3V

1 m resistance wire

3 V100 mA

crocodileclips

Fig. 2.1

(a) The student checks that the circuit is working by touching together the two crocodile clips.

(i) State what the student observes if the circuit is working correctly.

............................................................................................................................ [1]

(ii) Describe one possible fault that prevents the circuit working correctly.

..................................................................................................................................

............................................................................................................................ [1]

(b) When the circuit is working correctly, the student connects the two crocodile clips close together on the wire, as shown in Fig. 2.1.

(i) Describe what the student observes as the crocodile clips are slowly moved further apart on the wire.

..................................................................................................................................

............................................................................................................................ [1]

(ii) A circuit component is based on changing the length of the wire between two contacts.

1. State the name of this component.

...................................................................................................................... [1]

2. Draw its circuit symbol.

[1]

3. The component contains a long length of wire. Explain how the component is made small.

............................................................................................................................

...................................................................................................................... [1]

10

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[2]

The GCE class is investigating the potential differences across circuit components.3

Fig. 3.1 shows the apparatus used.

powerpack

lamp N

ammeter

lamp L lamp M

voltmeter

Fig. 3.1

(a) Draw a circuit diagram of the circuit shown in Fig. 3.1, using standard symbols.

(b) A student records the current IA, the potential difference VL across lamp L and the potential difference VM across lamp M.

0.65 AIA = ......................................................

0.9 VVL = ......................................................

1.0 VVM = ......................................................

(i) Calculate the potential difference VA across lamps L and M using the equation VA = VL + VM.

VA = ......................................................

11

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(ii) Calculate RA, the combined resistance of lamps L, M and N, using the equation

RA = VAIA

.

RA = ......................................................[2]

(iii) On Fig. 3.2, draw a pointer showing the current IA = 0.65 A.

0

0.20.4 0.6

A

0.8

1.0

Fig. 3.2 [1]

(c) The student rearranges the circuit so that the three lamps are in series with each other. He records the potential difference across each lamp in turn.

0.6 VVL = ......................................................

0.7 VVM = ......................................................

0.7 VVN = ......................................................

Calculate the potential difference VB across the three lamps using the equation VB = VL + VM + VN.

VB = ......................................................

(d) A student suggests that VA should be equal to VB.

State whether the results support this suggestion and justify your answer with reference to the results.

statement .........................................................................................................................

justification .......................................................................................................................

..........................................................................................................................................[2]

2

1

[Total 16 Marks]

12

MCQ Section:

[Turn over

A positively-charged rod is brought near to an isolated uncharged conducting sphere.

+

+

+

+

X Y

positively-charged rod

isolatedconducting sphere

insulator

What are the charges on sides X and Y of the sphere?

A Both X and Y are positively charged.

B Both X and Y are negatively charged.

C X is positively charged and Y is negatively charged.

D X is negatively charged and Y is positively charged.

A small uncharged metal sphere hangs from an insulating thread.

A negatively-charged rod moves close to the sphere.

insulatingthread

metal sphere–––

––

negatively-chargedrod

Which diagram shows the charges on the sphere and its final position?

A B C D

+ ++ +

– –– –

––

++

8

7

6

5

4

3

13

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Three identical cells are connected in parallel to a resistor.

What is the advantage of using three cells in parallel, rather than a single cell?

A Each cell produces more energy.

B Each cell supplies more charge.

C Each cell takes longer to run down.

D The total electromotive force (e.m.f.) is larger.

The diagram shows three resistors in parallel.

10Ω

5Ω

5Ω

What is the combined resistance?

A 0.50Ω B 2.0Ω C 20Ω D 250Ω

A student joins three 6Ω resistors as shown in the diagram.

6Ω

6Ω

6Ω

X Y

What is the total resistance between points X and Y?

A 0.5Ω B 2Ω C 6Ω D 18Ω

A lamp connected to a 12V supply converts energy at a rate of 36W.

How much energy will be converted in 10s?

A 30J B 36J C 120J D 360J

An immersion heater is labelled 12V, 60 W.

What is the current in the heater when connected to a 12V supply?

A 0.20A B 5.0 A C 12A D 60A

A lamp is rated at 60W on a 240V supply.

What is the current in the lamp when used normally?

A 0.25A B 4.0 A C 60A D 180A

11

10

9

14

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P, Q and R are electrical symbols.

P Q R

What do these symbols represent?

P Q R

A fuse resistor relay coil

B relay coil fuse resistor

C relay coil resistor fuse

D resistor fuse relay coil

The cost of electricity is 16c per kW h.

What is the cost of using a 3 kW heater for 4 hours?

A16

43×c B

4

163×c C 4 × 3 × 16c D 4 × 3 × 60 × 16c

The diagram shows a circuit used to find the resistance of lamp L.

Blocks P, Q and R represent the different components used.

12 V

P R

Q

L

Which is a correct possible choice of components to use for P, Q and R?

P Q R

A ammeter variable resistor voltmeter

B variable resistor voltmeter ammeter

C voltmeter ammeter variable resistor

D voltmeter variable resistor ammeter

14

13

12

15

[Turn over

A student connects the circuit shown.

1

2

3

4

Which switches must be closed for the bell to ring without lighting the lamp?

A 1 and 2 only B 1 and 3 only C 1, 3 and 4 only D 2, 3 and 4 only

The diagram shows two voltmeters, P and Q, connected to a potential divider.

XV

V

voltmeter P

voltmeter Q

The sliding connection at point X is moved towards the top of the diagram.

What happens to the reading on P and to the reading on Q?

reading on P reading on Q

A decreases decreases

B decreases increases

C increases decreases

D increases increases

An electric oven is connected to the mains supply using insulated copper wires. The wires become very warm.

What can be done to prevent so much heat being produced in the connecting wires?

A Use thicker copper wires.

B Use thinner copper wires.

C Use thicker insulation.

D Use thinner insulation.

16

15

16

[Turn over

The circuit shows a 24V battery connected to two resistors in series.

A

V

R

The reading on the ammeter is 2.0A and the reading on the voltmeter is 8.0V.

What is the resistance of resistor R?

A 0.25Ω B 4.0Ω C 10Ω D 16Ω

The diagram shows a circuit containing two identical lamps.

R

P

Q

Which switches must be closed to light both of the lamps?

A P and Q only

B P and R only

C Q and R only

D P, Q and R

16 A B C D

15 A B C D

14 A B C D

13 A B C D

12 A B C D

11 A B C D

10 A B C D

9 A B C D

17

Candidate Name:

Example

For question 1,

If you think B is the right answer, fill in

your answer sheet like this:

1 A B C D

Instructions

Shade

One

letter

only

for

each

question

Make

sure

you

put

your

answer

in

line

with

the

correct

question

number

1 A B C D

2 A B C D

3 A B C D

4 A B C D

5 A B C D

6 A B C D

7 A B C D

8 A B C D