AIEEE 2009 | Magnetic Effect of Current Question 175 | Physics

1

AIEEE 2009

MCQ (Single Correct Answer)

+4

-1

A current loop $$ABCD$$ is held fixed on the plane of the paper as shown in the figure. The arcs $$BC$$ (radius $$= b$$) and $$DA$$ (radius $$=a$$) of the loop are joined by two straight wires $$AB$$ and $$CD$$. A steady current $$I$$ is flowing in the loop. Angle made by $$AB$$ and $$CD$$ at the origin $$O$$ is $${30^ \circ }.$$ Another straight thin wire steady current $${I_1}$$ flowing out of the plane of the paper is kept at the origin. AIEEE 2009 Physics - Magnetic Effect of Current Question 173 English

AIEEE 2009 Physics - Magnetic Effect of Current Question 173 English

The magnitude of the magnetic field $$(B)$$ due to the loop $$ABCD$$ at the origin $$(O)$$ is :

A

$${{{\mu _0}I\left( {b - a} \right)} \over {24ab}}$$

B

$${{{\mu _0}I} \over {4\pi }}\left[ {{{b - a} \over {ab}}} \right]$$

C

$${{{\mu _0}I} \over {4\pi }}\left[ {2\left( {b - a} \right) + {\raise0.5ex\hbox{$\scriptstyle \pi $} \kern-0.1em/\kern-0.15em \lower0.25ex\hbox{$\scriptstyle 3$}}\left( {a + b} \right)} \right]$$

D

zero

2

AIEEE 2009

MCQ (Single Correct Answer)

+4

-1

A current loop $$ABCD$$ is held fixed on the plane of the paper as shown in the figure. The arcs $$BC$$ (radius $$= b$$) and $$DA$$ (radius $$=a$$) of the loop are joined by two straight wires $$AB$$ and $$CD$$. A steady current $$I$$ is flowing in the loop. Angle made by $$AB$$ and $$CD$$ at the origin $$O$$ is $${30^ \circ }.$$ Another straight thin wire steady current $${I_1}$$ flowing out of the plane of the paper is kept at the origin. AIEEE 2009 Physics - Magnetic Effect of Current Question 172 English

AIEEE 2009 Physics - Magnetic Effect of Current Question 172 English

Due to the presence of the current $${I_1}$$ at the origin:

A

The forces on $$AD$$ are $$BC$$ are zero.

B

The magnitude of the net force on the loop is given by $${{{I_1}I} \over {4\pi }}{\mu _0}\left[ {2\left( {b - a} \right) + {\raise0.5ex\hbox{$\scriptstyle \pi $} \kern-0.1em/\kern-0.15em \lower0.25ex\hbox{$\scriptstyle 3$}}\left( {a + b} \right)} \right].$$

C

The magnitude of the net force on the loop is given by $${{{\mu _0}I{I_1}} \over {24ab}}\left( {b - a} \right).$$

D

The forces on $$AB$$ and $$DC$$ are zero.

3

AIEEE 2008

MCQ (Single Correct Answer)

+4

-1

A horizontal overhead powerline is at height of $$4m$$ from the ground and carries a current of $$100A$$ from east to west. The magnetic field directly below it on the ground is
$$\left( {{\mu _0} = 4\pi \times {{10}^{ - 7}}\,\,Tm\,\,{A^{ - 1}}} \right)$$

A

$$2.5 \times {10^{ - 7}}\,T$$ southward

B

$$5 \times {10^{ - 6}}\,T$$ northward

C

$$5 \times {10^{ - 6}}\,T$$ southward

D

$$2.5 \times {10^{ - 7}}\,T$$ northward

4

AIEEE 2007

MCQ (Single Correct Answer)

+4

-1

A charged particle with charge $$q$$ enters a region of constant, uniform and mutually orthogonal fields $$\overrightarrow E $$ and $$\overrightarrow B $$ with a velocity $$\overrightarrow v $$ perpendicular to both $$\overrightarrow E $$ and $$\overrightarrow B, $$ and comes out without any change in magnitude or direction of $$\overrightarrow v $$. Then

A

$$\overrightarrow v = \overrightarrow B \times \overrightarrow E /{E^2}$$

B

$$\overrightarrow v = \overrightarrow E \times \overrightarrow B /{B^2}$$

C

$$\overrightarrow v = \overrightarrow B \times \overrightarrow E /{B^2}$$

D

$$\overrightarrow v = \overrightarrow E \times \overrightarrow B /{E^2}$$