If moving charges are positive, then current flows in the direction of the charges.

A. TrueB. False

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If moving charges are negative, then current flows in the direction of the charges.

A. TrueB. False

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What direction must the current be flowing though the bar if it is accelerating to the right.

A. UpB. Down

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A conducting wire with positive moving charges has current as depicted. In what direction is the resulting magnetic force?

A. to the leftB. to the rightC. towards the top of the

screenD. towards the bottom of

the screenE. into the screenF. out of the screenG. none of the above

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A conducting wire with negative moving charges has current as depicted. In what direction is the resulting magnetic force?

A. to the leftB. to the rightC. towards the top of the

screenD. towards the bottom of

the screenE. into the screenF. out of the screenG. none of the above

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Magnetic field lines are induced by the current in a circular loop. In what direction will the magnetic field point at the very center of the loop?

A. Towards the top of the loopB. Towards the bottom of the loopC. Towards the right of the loopD. Towards the left of the loopE. Out of the screen, normal to the loop.F. Into the screen, normal to the loop.G. Some strange off-center direction not

listed above.

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If the current carrying loop is replaced with two loops made of the same material, then the strength of the magnetic field in the center of the loops…

A. stays the sameB. is zero since the loops

magnetic fields cancel.C. doubles in strength.D. halves in strength.E. (none of the above) 0% 0%0%0%0%

If the current carrying loop is replaced by a loop with twice the radius, the strength of the magnetic field at the center of the loop….

A. stays the sameB. is four times the strengthC. doubles in strength.D. halves in strength.E. is ¼ the strength.F. (none of the above)

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