Magnetism and Electromagnetism

Worked examples (9)

• 1Match the unit to the quantity (Getting started)
• 2Convert the prefixes (Getting started)
• 3Power of a dynamo (Getting started)
• 4Rearrange for the current (Building confidence)
• 5Motor efficiency (Building confidence)
• 6Why P = IV needs no constant (Building confidence)
• 7Units in an induction experiment (Stretch)
• 8Scaling up to a power station (Stretch)
• 9Current and the motor effect (Stretch)

Model answers (9)

• ✓Model answer — 4SD0/1P style
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Worked examples (9)

• 1What a field line represents (Getting started)
• 2The drawing rules (Getting started)
• 3Why lines cannot cross (Getting started)
• 4Producing a uniform field (Building confidence)
• 5Two arrangements compared (Building confidence)
• 6Compare the field strength (Building confidence)
• 7Identify the unlabelled poles (Stretch)
• 8Where the field stops being uniform (Stretch)
• 9Why uniform fields are used (Stretch)

Model answers (9)

• ✓Model answer — 4SD0/1P style
• ✓Model answer — 4SD0/1P style
• ✓Model answer — 4SD0/1P style
• ✓Model answer — 4SD0/1P style
• ✓Model answer — 4SD0/1P style
• ✓Model answer — 4SD0/1P style
• ✓Model answer — 4SD0/1P style
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• ✓Model answer — 4SD0/1P style

Worked examples (9)

• 1Predict the force (Getting started)
• 2Which materials are magnetic? (Getting started)
• 3The repulsion test (Getting started)
• 4Compare hard and soft (Building confidence)
• 5Choose the material (Building confidence)
• 6The paper-clip chain (Building confidence)
• 7Why induction always gives attraction (Stretch)
• 8Making and destroying a magnet (Stretch)
• 9A freely suspended magnet (Stretch)

Model answers (9)

• ✓Model answer — 4SD0/1P style
• ✓Model answer — 4SD0/1P style
• ✓Model answer — 4SD0/1P style
• ✓Model answer — 4SD0/1P style
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• ✓Model answer — 4SD0/1P style
• ✓Model answer — 4SD0/1P style
• ✓Model answer — 4SD0/1P style

Worked examples (9)

• 1The iron filings method (Getting started)
• 2The plotting compass method (Getting started)
• 3Compare the two methods (Getting started)
• 4The three patterns (Building confidence)
• 5The neutral point (Building confidence)
• 6Precautions (Building confidence)
• 7Evaluate a flawed result (Stretch)
• 8Combining both methods (Stretch)
• 9Identify the arrangement from the pattern (Stretch)

Model answers (9)

• ✓Model answer — 4SD0/1P style
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• ✓Model answer — 4SD0/1P style

Worked examples (9)

• 1Evidence that a current makes a field (Getting started)
• 2The field around a straight wire (Getting started)
• 3Why a force acts (Getting started)
• 4The effect of the angle (Building confidence)
• 5All four changes (Building confidence)
• 6The d.c. motor (Building confidence)
• 7The loudspeaker (Stretch)
• 8Two changes at once (Stretch)
• 9Correct the explanation (Stretch)

Model answers (9)

• ✓Model answer — 4SD0/1P style
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• ✓Model answer — 4SD0/1P style
• ✓Model answer — 4SD0/1P style

Worked examples (9)

• 1What each finger represents (Getting started)
• 2A straightforward prediction (Getting started)
• 3Reading × and • symbols (Getting started)
• 4Conventional current versus electron flow (Building confidence)
• 5Apply it to a motor coil (Building confidence)
• 6The three reversal cases (Building confidence)
• 7When the rule does not apply (Stretch)
• 8Diagnose a 180° error (Stretch)
• 9Left or right hand? (Stretch)

Model answers (9)

• ✓Model answer — 4SD0/1P style
• ✓Model answer — 4SD0/1P style
• ✓Model answer — 4SD0/1P style
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• ✓Model answer — 4SD0/1P style
• ✓Model answer — 4SD0/1P style

Worked examples (9)

• 1When is a voltage induced? (Getting started)
• 2Increasing the induced voltage (Getting started)
• 3Cutting field lines (Getting started)
• 4How a generator works (Building confidence)
• 5The a.c. output graph (Building confidence)
• 6Rotating a magnet inside a coil (Building confidence)
• 7The bicycle dynamo (Stretch)
• 8Why a dynamo makes pedalling harder (Stretch)
• 9Slip rings or commutator? (Stretch)

Model answers (9)

• ✓Model answer — 4SD0/1P style
• ✓Model answer — 4SD0/1P style
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• ✓Model answer — 4SD0/1P style