Monday, 24 November 2014
Thursday, 20 November 2014
Wednesday, 19 November 2014
Tuesday, 11 November 2014
Mark scheme for test
1. (a) V
= I R (stated in any correct form);
= 0.4 × 7.5;
= 3; [Bald, correct answer scores 3 marks] 3
= 0.4 × 7.5;
= 3; [Bald, correct answer scores 3 marks] 3
(b) (i) 0.2 A; 1
(ii) 0.8 A; 1
(c) (i) A description to include:
1. increases;
2. (then) constant / levels out / stays the same
/ to a maximum; 2
(ii) temperature
changes / filament hotter / due to heat; 1
(iii) A description to include two from:
1. starts high / initial surge;
2. decreases (in right context);
3. (then) constant / levels out; 2
[10]
2. (a) chassis/metal casing/outer part/OWTTE;
[Allow back]
[Reject bottom/motor/door/pipes]
[Reject plastic casing] 1
[Allow back]
[Reject bottom/motor/door/pipes]
[Reject plastic casing] 1
(b) D; 1
(c) earth; fuse; live earth; 4 [6]
3. C
[1]
4. (a) (i) A
calculation to show:
·
V = IR;
V
= 0.3 ´
600;
= 180 V;[Allow ecf] 3
(ii) A
calculation to include:
Either
·
P = V ´ I =180 ´ 0.3;[Allow ecf from part (i)]
·
=54;
or V2/R = 1802/600
·
=
54;
or
·
I2R = 0.32 ´ 600;
·
=
54;
[Allow 1 mark if using wrong value of
resistance] 2
(b) An
explanation to include:
·
will increase;
·
greater current/less resistance in
circuit/greater V across blanket;
[Allow no resistance/no resistor]
[Do not accept power by itself for second marking point] 2
[Do not accept power by itself for second marking point] 2
[7]
5. (a) copper;
silver; 2
silver; 2
(b) (i) two forces pushing outwards;
horizontal; 2
[Reject curved lines for force]
horizontal; 2
[Reject curved lines for force]
(ii) An
explanation to include:
1. positive;
2. like (charges) repel; 2
[Ignore poles]
1. positive;
2. like (charges) repel; 2
[Ignore poles]
(iii) An
explanation to include:
1. aluminium is a conductor / OWTTE;
2. charge / current would flow to earth / OWTTE; 2
1. aluminium is a conductor / OWTTE;
2. charge / current would flow to earth / OWTTE; 2
(c) (i) Any two correct suggestions, for example,
Vander graaf /
lightning conductor / Plasma ball / photocopiers / spray painter /
precipitator (smoke cleaning) / insecticide sprays / particle accelerators / 2
inkjet printers;
lightning conductor / Plasma ball / photocopiers / spray painter /
precipitator (smoke cleaning) / insecticide sprays / particle accelerators / 2
inkjet printers;
(ii) Any
two correct suggestions, for example, shocks / dust /
electronic circuit damage / hair standing on end / explosions (fuel) /
could turn pace maker off / tumble dryer / lighting; 2
electronic circuit damage / hair standing on end / explosions (fuel) /
could turn pace maker off / tumble dryer / lighting; 2
[12]
6. A
[1]
7. B
[1]
8. (a) cooker;
highest power/most current; 2
highest power/most current; 2
(b) biggest
current for same voltage/needs high current/
high power; 2
largest current with lowest resistance;
high power; 2
largest current with lowest resistance;
(c) thick cables have a lower resistance;
thick cables produce less heat; 2
thick cables produce less heat; 2
[6]
9. (i) An explanation to include:
1. friction between duster and comb;
2. charge transferred in the process/ moved off /
pull; 2
[Ignore reference to sign of charge]
(ii) A
suggestion to include:
1. paper contains charges / paper charged;
2. opposite charges;
3. attract(ed) to comb; 2
(iii) comb
earthed / metals conduct / metals cannot be charged /
metal is not charged / charge goes to hand; 1
metal is not charged / charge goes to hand; 1
[5]
10. (a) (i) voltages alternating/positive and negative;
[Allow voltage changes for 1 mark] 2
[Allow voltage changes for 1 mark] 2
(ii) (a) - (+)6 (V) 1
(b) - (-)6 (V) (Allow
ecf from (A))
[Allow 6 in (B) if not awarded in (A)] 1
[Allow 6 in (B) if not awarded in (A)] 1
(iii) same frequency;
reduced amplitude/smaller voltage; 2
reduced amplitude/smaller voltage; 2
[6]
