Hey there! Sign in to join this conversationNew here? Join for free
    • Thread Starter
    Offline

    0
    ReputationRep:
    http://filestore.aqa.org.uk/subjects...1-QP-JUN12.PDF

    Could someone pls explain why the answer to question 24 is C ??
    Offline

    20
    ReputationRep:
    (Original post by HG1)
    http://filestore.aqa.org.uk/subjects...1-QP-JUN12.PDF

    Could someone pls explain why the answer to question 24 is C ??
    That's when the fastest change in magnetic flux is.
    • Thread Starter
    Offline

    0
    ReputationRep:
    (Original post by morgan8002)
    That's when the fastest change in magnetic flux is.
    Ah thanks mate , would you mind explaining in more detail ? Sorry my understanding is lacking
    Offline

    20
    ReputationRep:
    (Original post by HG1)
    Ah thanks mate , would you mind explaining in more detail ? Sorry my understanding is lacking
    The magnitude of the induced emf is equal to the magnitude of the rate of change of magnetic flux in the second coil. By Ohm's law this is proportional to the induced current. So the magnitude of the induced current is proportional to the magnitude of the rate of change of the magnetic flux across the second coil.

    On the other hand, the magnetic flux across the second coil is proportional to the magnetic flux density, which is proportional to the current through the first coil.

    So the magnitude of the induced current in the second coil is proportional to the magnitude of the rate of change of the current though the first coil.

    The current in the first coil only increases slowly, so the greatest magnitude of the rate of change of the current in the first coil is when the switch is opened and the current suddenly drops to 0.
    • Thread Starter
    Offline

    0
    ReputationRep:
    [QUOTE=morgan8002;64122995]The magnitude of the induced emf is equal to the magnitude of the rate of change of magnetic flux in the second coil. By Ohm's law this is proportional to the induced current. So the magnitude of the induced current is proportional to the magnitude of the rate of change of the magnetic flux across the second coil.

    On the other hand, the magnetic flux across the second coil is proportional to the magnetic flux density, which is proportional to the current through the first coil.

    So the magnitude of the induced current in the second coil is proportional to the magnitude of the rate of change of the current though the first coil.

    The current in the first coil only increases slowly, so the greatest magnitude of the rate of change of the current in the first coil is when the switch is opened and the current suddenly drops to 0.[/QUOTE

    Thank you so much ! It's so much more clear now
    Offline

    20
    ReputationRep:
    (Original post by HG1)

    Thank you so much ! It's so much more clear now
    No problem.
 
 
 
Poll
Do you agree with the PM's proposal to cut tuition fees for some courses?

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Write a reply...
Reply
Hide
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.