Physics 5 question.

3. In London the Earth's magnetic field has a magnetic flux density
of 4.8 x 10-5 T at 66° to the horizontal as shown in the diagram.

Calculate the magnitude of the horizontal component of the Earth's
magnetic field in London. (2)

For a conductor of length l moving at a speed v perpendicular to a
field of flux density B, the induced voltage V between the ends of the
conductor is given by: V = B l v
A metal scaffolding pole falls from rest off a high building.
The pole is aligned horizontally in an east-west direction.
The Earth's magnetic field lines at this point lie in a north-south direction.

Calculate the induced voltage across the pole 2.0 s after it started to fall. (3)

What would be the induced voltage after 2.0 s if the pole were aligned in
a north-south direction?
Explain your answer. (2)

Can anyone please answer the question in bold?

I've written that the it will remain same as direction of motion is same ,..

tsr.JPG12.8KB

Reply 1

specialhelen

Paxi

3. In London the Earth's magnetic field has a magnetic flux density
of 4.8 x 10-5 T at 66° to the horizontal as shown in the diagram.

Calculate the magnitude of the horizontal component of the Earth's
magnetic field in London. (2)

For a conductor of length l moving at a speed v perpendicular to a
field of flux density B, the induced voltage V between the ends of the
conductor is given by: V = B l v
A metal scaffolding pole falls from rest off a high building.
The pole is aligned horizontally in an east-west direction.
The Earth's magnetic field lines at this point lie in a north-south direction.

Calculate the induced voltage across the pole 2.0 s after it started to fall. (3)

What would be the induced voltage after 2.0 s if the pole were aligned in
a north-south direction?
Explain your answer. (2)

Can anyone please answer the question in bold?

I've written that the it will remain same as direction of motion is same ,..

June 2003 question 3 right - from the markscheme

induced emf = 0

rod does not cut magnetic field lines/no flux cutting/ no change in flux

i have all the markschemes for PHY5 and 6 edexcel for the new sylabus - so PM me if anyone wants answers - or to let me know if there are any more quires

Reply 2

mackin boi

1

Paxi

3. In London the Earth's magnetic field has a magnetic flux density
of 4.8 x 10-5 T at 66° to the horizontal as shown in the diagram.

Calculate the magnitude of the horizontal component of the Earth's
magnetic field in London. (2)

For a conductor of length l moving at a speed v perpendicular to a
field of flux density B, the induced voltage V between the ends of the
conductor is given by: V = B l v
A metal scaffolding pole falls from rest off a high building.
The pole is aligned horizontally in an east-west direction.
The Earth's magnetic field lines at this point lie in a north-south direction.

Calculate the induced voltage across the pole 2.0 s after it started to fall. (3)

What would be the induced voltage after 2.0 s if the pole were aligned in
a north-south direction?
Explain your answer. (2)

Can anyone please answer the question in bold?

I've written that the it will remain same as direction of motion is same ,..

Horizontal Component = (4.8*10^-5)*cos66 = 1.95*10^-5 T

V=Blv B=1.95*10^-5 T l=2.5m
v = u + at = 9.81*2 = 19.62 m/s

Therfore V = (1.95*10^-5)*(2.5)*(19.62) = 9.56*10^-4 V

The induced voltage would be 0V as the pole would be travelling parallel to the earths magnetic field and so no flux cutting would occur (no flux linkage). By Faraday's Law you need Flux Linkage to induce and e.m.f.

Physics 5 question.

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