Circular loop of a wire and a long strai...

Circular loop of a wire and a long straight wire carry currents and respectively as shown in figure. Assuming that these are placed in the same plane, the magnetic fields will be zero at the centre of the loop when separation H Circular wire Straight wire

`(I_(e)R)/(I_(c)pi)`

`(I_(c)R)/(I_(e)pi)`

`(piI_(c))/(I_(c)R)`

`(piI_(c))/(I_(e)R)`

Text Solution

Verified by Experts

The correct Answer is:

Magnetic fieds at the centre O of the curcular current loop is `B_(1)=mu_(0)/(4pi)(2piI_(c))/("R")`
Magnetic field at the centre O of the circular loop due to current through long straight wire is `B_(2)=(mu_(0))/(4oi)(2I_(e))/(H)`.
As the resultant magnetic field at O is zero (given) hence `B_(1)` and `B_(2)` must be equal in magnitude and opposite in direction,So
`(mu_(0))/(4pi)(2piI_(c))/("R")=(mu_(0))/(4pi)(2Ie_(e))/(H)=(I_(e)R)/(piI_(c))`

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Circular loop of a wire and a long straight wire carry current I_(c ) and I_(e ) respectively as shown in figure. Assuming that these are placed in the same plane. The magnetic field will be zero at the centre of the loop when the separation H is:

`(I_(e )R)/(I_(c )pi)`

`(I_(c )R)/(I_(e )pi)`

`(piI_(c ))/(I_(e)pi)`

`(I_(e )pi)/(I_(c )R)`

A circular loop of radius r carries a current i .How should a long, straight wire carrying a current 3i be placed in the plane of the circle so that the magnetic field at the centre of the loop becomes zero?

At at distances `(3r)/pi` from the centre of loop

At at distances `(2r)/pi` from the centre of loop

At at distances `(2r)/(3pi)` from the centre of loop

Not possible

There is a circular loop carrying current and another straight wire carrying current is placed along its axis. The straight wire

will apply radial inward force on the circular loop.

will apply radial outward force on the circular loop.

will apply force radially inward or outward, depending on the direction of currents.

will not exert any force on the circular loop.