Solved Lab 8 Worksheet (Electromagnetism, Right Hand Rule ... - Free Printable

Let's go through each section of the Lab 8 Worksheet on Electromagnetism, Right Hand Rule, and Lenz’s Law, step by step.

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A) Magnetic Field Produced by Current in a Wire

Use the Right-Hand Rule for straight wires:
Grasp the wire with your right hand, thumb pointing in the direction of conventional current (positive to negative). Your fingers curl in the direction of the magnetic field.

#### 1) Current direction: To the right
- Wire is horizontal, current → to the right.
- At a point above the wire: magnetic field circles counterclockwise around the wire.
- So, above the wire: into the page (×)
- Below the wire: out of the page (○)

But since the question asks to "show" the magnetic field, we typically draw concentric circles around the wire with arrows indicating direction.

> ✔ Answer: The magnetic field forms concentric circles around the wire. Above the wire, it points into the page (×), below it, out of the page (○). Direction: counterclockwise when viewed from left to right.

#### 2) Current direction: Into the page (X)
- This means current is going into the page at a point.
- Use right-hand rule: Point your thumb into the page; your fingers curl clockwise around the point.

> ✔ Answer: Magnetic field lines form clockwise circles around the point.

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B) Deflection of Charged Particles in Magnetic Fields

Use the Right-Hand Rule for positive charges:
F = q(v × B)
- Point fingers in direction of velocity (v).
- Curl toward B-field.
- Thumb gives force direction for positive charge.
- For electrons (negative), reverse the direction.

#### 1) Magnetic field into the page (×), electron moving right
- v → right, B → into page (×)
- For positive charge: RHR → Force upward
- But this is an electron (negative) → force is downward

> ✔ Answer: Electron deflects downward

#### 2) Magnetic field out of the page (○), electron moving right
- v → right, B → out of page (○)
- For positive charge: RHR → Force downward
- Electron → opposite → upward

> ✔ Answer: Electron deflects upward

#### 3) Magnetic field pointing up, electron moving right
- v → right, B → up
- For positive: RHR → F → into the page
- Electron → out of the page

> ✔ Answer: Electron deflects out of the page (○)

#### 4) Magnetic field pointing right, electron moving right
- v → right, B → right → angle θ = 0°
- F = qvB sinθ = qvB sin(0) = 0

> ✔ Answer: No deflection — particle continues straight.

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C) Magnetic Field of Each Solenoid

Use the Right-Hand Rule for solenoids:
Grasp coil with right hand, fingers in direction of current; thumb points to North pole of solenoid.

#### Left Solenoid:
- Battery connected: current flows from (+) to (–)
- So, current enters the left side of the solenoid.
- Winding direction: assume standard wrap (clockwise or counterclockwise? Let’s trace).

Looking at the diagram:
- Current enters from bottom-left → goes up on the front side → then loops around.
- So, on the front face, current is upward on the left side.

Apply RHR:
- Curl fingers in direction of current → thumb points to the right → so right end is North pole

> ✔ Answer: Magnetic field inside solenoid points to the right (→)

#### Right Solenoid:
- This one has a bar magnet near it, but the question is just about the solenoid’s magnetic field based on current?
Wait — actually, the second figure shows a bar magnet and a solenoid, but the question says: “Which direction is the magnetic field of each solenoid shown below?”

But there are two solenoids:

1. First solenoid: powered by battery → we did above → field → right
2. Second solenoid: no battery, but has a bar magnet nearby?

Wait — looking again: the second figure is a rectangle with poles labeled.

Actually, the image shows a solenoid with a bar magnet and a separate solenoid with a battery.

But the question C says: “Which direction is the magnetic field of each solenoid shown below?” and shows two diagrams:

- One solenoid with a battery (left)
- One solenoid with a bar magnet approaching (right) — but that’s part D.

Wait — perhaps the second one is not a solenoid? Or maybe it's asking for the induced field?

No — the question says “each solenoid shown below” — and both are solenoids.

But the second solenoid has no battery, only a bar magnet being moved — so no current unless induced.

But in part C, it seems to be asking for inherent magnetic field due to current — so likely only the first solenoid has current.

But wait — the second diagram shows a bar magnet and a solenoid — but no power source.

So perhaps the second solenoid has no current, hence no magnetic field?

But the question says “each solenoid” — maybe it's asking to determine the direction of the magnetic field based on the current flow.

But only the first solenoid has a battery.

Wait — let's look closely.

The first solenoid has a battery:
- Current flows from (+) to (–): so from bottom to top on the left side.
- So current enters the solenoid from bottom, goes up on the left, wraps around → on the front, current is upward on the left, downward on the right.

Using RHR:
- Wrap fingers around solenoid in direction of current → thumb points to the right → so right end is North, field inside → right

✔ Answer: Magnetic field inside solenoid points to the right

Now the second solenoid — it has a bar magnet near it, but no battery, so no current → no magnetic field from solenoid itself.

But the diagram shows a rectangle with dots and crosses — maybe it's a different type?

Wait — the second figure in C is a rectangle with N and S poles labeled, and a solenoid next to it.

But the question is: “Which direction is the magnetic field of each solenoid shown below?”

So if the second solenoid has no current, its magnetic field is zero.

But perhaps the question is asking for the magnetic field produced by the solenoid, assuming current flows in the direction implied?

Wait — actually, the second solenoid has no battery, so unless it's being induced, no field.

But the question might be misinterpreted.

Alternatively, perhaps the second solenoid is powered, but not shown?

Looking again — no, the second one has a bar magnet and no battery.

So likely, only the first solenoid has a magnetic field.

But the question says “each solenoid”, implying both.

Wait — perhaps the second diagram is not a solenoid? It looks like a bar magnet.

Ah! Actually, the second figure is a bar magnet with N and S poles, and a solenoid next to it.

But the question says: “Which direction is the magnetic field of each solenoid shown below?”

So only one solenoid is shown with a battery — the first one.

The second figure is a bar magnet, not a solenoid.

So likely, only one solenoid is in part C.

But the layout shows two diagrams — one solenoid with battery, one bar magnet.

Possibly a typo.

Assuming only the first solenoid is relevant.

✔ Answer: Magnetic field inside solenoid points to the right (→)

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D) Induced Current in Solenoids – Lenz’s Law

Lenz’s Law: The induced current creates a magnetic field that opposes the change in magnetic flux.

Use Right-Hand Rule to find direction of current based on desired magnetic field.

#### 1) Move magnet closer (N pole toward solenoid)
- Magnet’s N pole approaching → increasing outward magnetic field into solenoid.
- Solenoid will oppose this → create a N pole at the left end to repel the approaching N pole.
- So, left end becomes N, right end S.
- Use RHR: to make left end N, current must flow counterclockwise when viewed from left → so current flows from A to B?

Wait — let’s define:

- Terminal A is on the left, B on the right.
- If we want left end of solenoid to be N, then current must flow into the solenoid at the left, and up on the front.
- So current enters at A, goes up on front → so A → B in the wire?

Wait — the wire connects A and B — which is the external circuit.

If current flows from A to B in the wire, that means it’s entering the solenoid at A (left), and flowing up on the front.

Yes — that produces a N pole at the left.

✔ Answer: Induced current flows A → B

#### 2) Move magnet away (S pole moving away, N pole facing solenoid)
- Magnet is being moved away — so flux decreasing.
- Original field: N pole near solenoid → field into solenoid (from N to S).
- As magnet moves away, flux decreases → solenoid wants to maintain the field → create N pole at right end to attract the retreating N pole.
- So, right end becomes N, left end S.
- To make right end N, current must flow clockwise when viewed from right → so on the front, current flows downward.
- So, current enters solenoid at B, exits at A → so current flows B → A in the wire.

✔ Answer: Induced current flows B → A

#### 3) Close the switch
- Switch closes → current starts flowing in solenoid → magnetic field builds up.
- But what is the direction of current? From battery: + to – → so current flows into the solenoid at the left, up on front → same as earlier → creates N pole at right.
- But now, we’re closing the switch, so current increases → flux increases → induced current opposes this.
- So induced current will try to create a field opposite to the increasing field.
- Original field: right end N → so induced field should have right end S, left end N.
- So, induced current must produce N at left, S at right.
- That means current must flow counterclockwise when viewed from left → so A → B in the wire.

Wait — but this is the same direction as the main current?

No — induced current is in the same loop — but when you close the switch, the change in flux is due to the increase in current.

But the induced EMF opposes the change, so it tries to reduce the increase.

So the induced current flows in the opposite direction to the main current.

But in this case, the main current is flowing A → B (since battery drives current from A to B).

So induced current should flow B → A to oppose the increase.

Wait — but when you close the switch, the solenoid resists the buildup of current → so induced current is opposite to the applied current.

So induced current flows B → A

✔ Answer: Induced current flows B → A

#### 4) Open the switch
- Switch opens → current stops → magnetic field collapses.
- Flux decreases → induced current tries to maintain the field.
- Original field had right end N → so induced current tries to create right end N again.
- So induced current must flow in same direction as original current → A → B

✔ Answer: Induced current flows A → B

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✔ Final Answers Summary:

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#### A) Magnetic Field from Current

1) Current to the right → Magnetic field: counterclockwise around wire (into page above, out below)
2) Current into page → Magnetic field: clockwise circles

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#### B) Particle Deflection

1) B into page, e⁻ right → down
2) B out of page, e⁻ right → up
3) B up, e⁻ right → out of page (○)
4) B right, e⁻ right → no deflection

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#### C) Solenoid Magnetic Field

- Solenoid with battery: current flows up on front → field points to the right (→)

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#### D) Induced Current (Lenz’s Law)

1) Move magnet closer (N pole) → induced current: A → B
2) Move magnet away (N pole) → induced current: B → A
3) Close the switch → induced current: B → A
4) Open the switch → induced current: A → B

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