Recent questions tagged ncert

Five long wires $A,B,C,D$ and $E$ each carrying current I are arranged to form edges of a pentagonal prism as shown in figure. Each carries current out of the plane of paper . What will be the magnetic induction at a point on the axis =0 ? Axis is at a distance R from each wire ?

asked Aug 3, 2015 by meena.p

1 answer

A multi range current meter can be constructed by using a galvanometer circuit as shown in figure . We want a current meter that can measure $10\;mA,100\;mA$ and $1\;A$ using a galvanometer of resistance $10 \Omega$ and that produces maximum deflection for current $1\;mA$ Find $S_1,S_2$ and $S_3$ that have to be used

asked Aug 3, 2015 by meena.p

1 answer

A uniform conducting wire of length $12a$ and resistance R is wound up as a current carrying coil in the shape of an equilateral a regular hexagon of side a .The coil is connected to a voltage source of $V_0$ Find the magnetic moment of the coil .

asked Jul 31, 2015 by meena.p

1 answer

A uniform conducting wire of length $12a$ and resistance R is wound up as a current carrying coil in the shape of an equilateral square of side a. the coil is connected to a voltage source of $V_0$ Find the magnetic moment of the coil .

asked Jul 31, 2015 by meena.p

1 answer

A uniform conducting wire of length $12a$ and resistance R is wound up as a current carrying coil in the shape of an equilateral triangle of side a. the coil is connected to a voltage source of $V_0$ Find the magnetic of the coil .

asked Jul 31, 2015 by meena.p

1 answer

An electron and a positron are released $(0,0,0)$ and $(0,01.5 \;R)$ respectively , in a uniform magnetic field $\overrightarrow{B} =B_0 \hat i$, each with an equal momentum of magnitude $P= eBR$ Under what condition on the direction of momentum will the orbit be non- intersecting circles.

asked Jul 31, 2015 by meena.p

1 answer

A rectangular conducting loop consists of two wires on two opposite sides of length l joined together by rod of length d. The wires are each of the same material but with cross - section differing by a factor of 2. The thicker wire has a resistance R and the rods of low resistance , Which in turn are connected to a constant voltage source $V_0$ the loop is placed in uniform magnetic field B at 45 to its plane . Find the $T$ the torque exerted by the magnetic field on the loop about an axis through the centers of rods.

asked Jul 31, 2015 by meena.p

1 answer

A 100 turn rectangular coil $ABCD$ is hung from one arm of a balance(as shown in the figure) . A mass 500 g is added to the other arm to balance the weight of the coil . A current $4.9\;A$ passes through the coil and a constant magnetic field of $0.2 \;T$ acting inward (in xz plane) is switched on such that only arm CDof length 1 cm lies in the field . Hoe much additional mass 'm' must be added to regain the balance ?

asked Jul 31, 2015 by meena.p

1 answer

A long straight wire carrying current of $25\;A$ rests on a table as shown in the figure. Another wire $PQ$ of length $1\;m$ mass $2.5\;g$ carries the same current but in the opposite direction. the wire $PQ$ is free opposite direction. The wire PQ is free to slide up and down . To what height will PQ rise ?

asked Jul 31, 2015 by meena.p

1 answer

A multi range voltmeter can be constructed by using a galvanometer circuit as shown in the figure. We want to construct a voltmeter that can measure $2V,20V$ and $200\;V$ using a galvanometer of resistance $10\Omega$ and that produces maximum deflection for current of $1mA$ Find $R_1,R_2$ and $R_3$ that have to be used

asked Jul 31, 2015 by meena.p

1 answer

Two long wires carrying current $I_1$ and $I_2$ are arranged as shown in figure. the one carrying current $I_1$ is along the x-axis . the other carrying current $I_2$ is along a line parallel to the y-axis , given by $x=0$ and $z=d$ find the force exacted at $O_2$ because of the wire along the x-axis

asked Jul 31, 2015 by meena.p

1 answer

Do magnetic forces obey Newton's third law : Verify for two current elements $\overrightarrow{dl_1}= dl \hat i$ located at the origin and $\overrightarrow{dl_2}= dl \hat j$ located at $(0,R,0). Both carry current I.

asked Jul 30, 2015 by meena.p

1 answer

An electron enters with a velocity $\overrightarrow{v} =v_0 \hat i$ into a cubical region (faces parallel to coordinate plane ) in which there are uniform electric and magnetic fields. The orbit of the electron in front to spiral down inside the cube in plane parallel to the x-y plane . Suggest a configuration of fields $\overrightarrow{E}$ and $\overrightarrow{B}$ that can lead to it.

asked Jul 30, 2015 by meena.p

1 answer

A charged particle of charge e and mass m is moving in an electric field $\overrightarrow{E}$ and magnetic field $\overrightarrow{B}$. Construct dimension less quantities and quantities of dimension $[T]^{-1}$

asked Jul 30, 2015 by meena.p

1 answer

A current carrying loop consists of 3 identical quarter circles of radius R, lying in the positive quadrants of $x-y ,y-z$ and $z-x$ planes , with their centers at the origin joined together . Find the direction and magnitude to $\overrightarrow{B}$ at the origin .

asked Jul 30, 2015 by meena.p

1 answer

The magnetic force depends on $\overrightarrow{v}$ which depends on the inertial frame of reference . Does then the magnetic force differ from inertia frame to frame ?

asked Jul 30, 2015 by meena.p

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what will the motion of a charged particle in a cyclotron if the frequency of the radio frequency field is doubled ?

asked Jul 30, 2015 by meena.p

1 answer

A force that does not work must be velocity dependent force. Is this statement true or false

asked Jul 30, 2015 by meena.p

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The cyclotron frequency $W= \large\frac{eB}{m}$ has correct dimension of $[T]^{-1}$. Is this statement true or false

asked Jul 30, 2015 by meena.p

1 answer

A changed partice would continue to move with a constant velocity in a region where in ,

asked Jul 30, 2015 by meena.p

1 answer

A cubical region of space is filled with some uniform electric and magnetic fields . An electron enters the cube magnetic fields. An electron enters the cube across one of its faces with velocity $\overrightarrow {v}$ and a position enters via opposite face with velocity - $\overrightarrow v$ At this instant .

asked Jul 30, 2015 by meena.p

1 answer

Two identical current carrying coaxial loops carry current I in an opposite sense. A simple amperian loop passes through both of them once. Calling the loop as C,

asked Jul 29, 2015 by meena.p

1 answer

Consider a wire carrying a steady current , I placed in a uniform magnetic field $ \overrightarrow B$ perpendicular to its length . Consider the charge inside the wire. It is known that magnetic forces do not work. This implies the

asked Jul 29, 2015 by meena.p

1 answer

The gyro- magnetic ratio of an electron in an H- atom , according to Bohr model is

asked Jul 29, 2015 by meena.p

1 answer

A circular loop of magnetic moment M is in an arbitrary orientation in an external magnetic field $\overrightarrow{B}$ . The work done to rotate the loop by $30^{\circ}$about an axis perpendicular to its plane is

asked Jul 29, 2015 by meena.p

1 answer

In a cyclotron, a changed particle

asked Jul 29, 2015 by meena.p

1 answer

An electron is projected with uniform velocity at the axis of a current carrying long solenoid. Which of the following is true ?

asked Jul 29, 2015 by meena.p

1 answer

A current carrying circular loop of radius R is placed in the x-y plane with center at the orgin . Half of the loop with $ x >0$ is now bent so that it now lies in the $y-z$ plane .

asked Jul 29, 2015 by meena.p

1 answer

Biot -savart law indicates that the moving electrons (velocity $\overrightarrow{v}$) produce a magnetic field $\overrightarrow{B}$ such that

asked Jul 29, 2015 by meena.p

1 answer

Two changed particles traverse identical helical paths in a completely opposite sense in a uniform magnetic field $\overrightarrow{B} =B_0 \hat k$

asked Jul 29, 2015 by meena.p

1 answer

A galvanometer coil has a resistance of $15 \Omega$ and the meter shows full deflection scale for a current of $4\;mA$ . How will you convert the meter into a voltmeter of range $0\; to\; 6\;A$ ?

asked Jul 29, 2015 by meena.p

1 answer

A galvanometer coil has a resistance of $12 \Omega$ and the meter shows full scale deflection for a current of $3\;mA$ . How will you convert the meter into a voltmeter of range $0\; to\; 18\;V$ ?

asked Jul 29, 2015 by meena.p

1 answer

A solenoid 60 cm long and radius $4.0\;cm$ has 3 layers of winding of 300 turns each . A 2.0 cm long wire of mass $2.5 \;g$ inside the solenoid (near its center) normal to its axis, both the wire and the axis of the solenoid are in the horizontal plane. The wire is connected through two leads parallel to the axis of the solenoid to the external battery which supplies a current of $6.0$ in the sense of circulation ) in the windings of the solenoid can support the weight of the wire $(g= 9.8 m/g^2)$

asked Jul 29, 2015 by meena.p

1 answer

A circular coil of 20 turns and radius $10\;cm$ is placed in a uniform magnetic field of $0.10\;T$ normal to the plane of the coil. If the current in the coil is $5.0 \;A$ What is the average force on each electron in the due to the magnetic field ?

asked Jul 29, 2015 by meena.p

1 answer

A circular coil of 20 turns and radius $10\;cm$ is placed in a uniform magnetic field of $0.10\;T$ normal to the plane of the coil. If the current in the coil is $5.0 \;A$ What is the total force on the coil ?

asked Jul 28, 2015 by meena.p

1 answer

A circular coil of 20 turns and radius $10\;cm$ is placed in a uniform magnetic field of $0.10\;T$ normal to the plane of the coil. If the current in the coil is $5.0 \;A$ What is the total torque on the coil ? (The coil is made of copper wire of cross sectional area $`10^{-5}\;m^2$ and the free electron density is given to be $10^{29}/m^3$

asked Jul 28, 2015 by meena.p

1 answer

A uniform magnetic field of $3000\;G$ is established along the positive z- direction . A rectangular loop of sides $10\;cm$ and $5\;cm$carries a current of $12\;A$. What is the torque on the loop in the case as shown in the figure? What is the force in this case ?

asked Jul 28, 2015 by meena.p

1 answer

A uniform magnetic field of $3000\;G$ is established along the positive z- direction . A rectangular loop of sides $10\;cm$ and $5\;cm$carries a current of $12\;A$. What is the torque on the loop in the case as shown in the figure? What is the force in this case ?

asked Jul 28, 2015 by meena.p

1 answer

A uniform magnetic field of $3000\;G$ is established along the positive z- direction . A rectangular loop of sides $10\;cm$ and $5\;cm$carries a current of $12\;A$. What is the torque on the loop in the given fig? What is the force in this case?

asked Jul 28, 2015 by meena.p

1 answer

A uniform magnetic field of $3000\;G$ is established along the positive z- direction . A rectangular loop of sides $10\;cm$ and $5\;cm$carries a current of $12\;A$. What is the torque on the loop in the fig? What is the force in this case ?

asked Jul 28, 2015 by meena.p

1 answer

A uniform magnetic field of $3000\;G$ is established along the positive z- direction . A rectangular loop of sides $10\;cm$ and $5\;cm$carries a current of $12\;A$. What is the torque on the loop in the fig? What is the force in this case? Does state correspond to equilibrium ?

asked Jul 28, 2015 by meena.p

1 answer

A uniform magnetic field of $3000\;G$ is established along the positive z- direction . A rectangular loop of sides $10\;cm$ and $5\;cm$carries a current of $12\;A$. What is the torque on the loop in the fig? What is the force ?

asked Jul 28, 2015 by meena.p

1 answer

A uniform magnetic field of $1.5 \;T$ exists a cylindrical region $10.0 \;cm$ its direction parallel to the axis along east to west. A wire carrying current of $7.0 \;A$ in the north to south direction passes through this region . What is the magnitude and direction of the force of the wire if the wire in the N-S direction is lowered from the axis by a distance of $6.0 \;cm$? intended the axis ?

asked Jul 28, 2015 by meena.p

1 answer

A uniform magnetic field of $1.5 \;T$ exists a cylindrical region $10.0 \;cm$ its direction parallel to the axis along east to west. A wire carrying current of $7.0 \;A$ in the north to south direction passes through this region . What is the magnitude and direction of the force on the wire if the wire is turned from N-S to north east -north west direction ?

asked Jul 28, 2015 by meena.p

1 answer

A uniform magnetic field of $1.5 \;T$ exists a cylindrical region $10.0 \;cm$ its direction parallel to the axis along east to west. A wire carrying current of $7.0 \;A$ in the north to south direction passes through this region . What is the magnitude and direction of the force of the wire is the wire intended the axis ?

asked Jul 28, 2015 by meena.p

1 answer

The wires which connected the battery of an automobile to its starting motor carrying a current of $300\;A$ (for a short time ). What is the force per unit length between the wires , if they are $70\;cm$long and $1.5 \;cm$ apart? Is the force attractive or repulsive ?

asked Jul 28, 2015 by meena.p

1 answer

A straight horizontal conducting rod of length $0.45\;m$ and mass $60\;g$ is suspended by two vertical wires at its ends. A current of $5.0\;A$ is setup in the rod through the wires . What will be the total tension in the wires if the direction of current is reversal keeping the magnetic field normal to the conductor in order that the tension in the wires is zero?(Ignore the mass of wires ) $g= 9.8 \;m/s^2$

asked Jul 28, 2015 by meena.p

1 answer

A straight horizontal conducting rod of length $0.45\;m$ and mass $60\;g$ is suspended by two vertical wires at its ends. A current of $5.0\;A$ is setup in the rod through the wires . What magnetic field should be setup normal to the conductor in order that the tension in the wires is zero?

asked Jul 28, 2015 by meena.p

1 answer

A magnetic field using using Helmholtz coils is uniform in a small region and has a magnitude of $0.75\;T$ .In the same region a uniform electrostatic field is maintained in a direction normal to the common axis of the coils. A narrow beam of (single species) changed particles all accelerated through $15\;KV$ enters this region in a direction perpendicular to both the axis of the coils and the electrostatic field. If the beam remains undetected when the electro static field is $9 \times 10^{-5}V/m$ making a simple guess as to what the beam contains . Is the answer unique?

asked Jul 27, 2015 by meena.p

1 answer

An electron travelling west to east enters a chamber having a uniform electrostatic field in north to south direction . specify the direction in which a uniform magnetic field should be set up to prevent electron from deflecting its straight line path .

asked Jul 27, 2015 by meena.p

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