Magnetic Field Due to a Straight Current Carrying Conductor

Q. 86. A closely wound solenoid 80 cm long has 5 layers of winding of 400 turns each. The diameter of the solenoid is 1.8 cm. If the current carried is 8.0 A , estimate the magnitude of magnetic field B inside the solenoid near its centre.

Q.

State the form of magnetic field lines around a straight current-carrying conductor.

Q.

A cylindrical wire of radius $0.5mm$ and conductivity $5\times {10}^{7}S/m$ is subjected to an electric field of $10mV/m$. The expected value of current in the wire will be $x^3\pi mA$. The value of $x$ is ____.

Q. A long wire carries a steady current. It is bent into a circle of one turn and the magnetic field at the centre of the coil is B. It is then bent into a circle loop of n turns. The magnetic field at the centre of the coil will be?

1. $nB$
2. $n^{2}B$
3. $2nB$
4. $2n^{2}B$

Q.

Name the rule for finding the direction of magnetic field produced by a straight current-carrying conductor.

Q. when we increase the number of turns per unit length in a solenoid then will the magnetic field at the centre will increase or decrease or will remain same?

Q. The motion of a charged particle can be used to distinguish between a magnetic field and electricfield in a certain region by firing the charge (1) Parallel to the field(2) From opposite directions in 1 option the charge particle will accelerate (if charge is positive) in the presence of elcectric field and in case 2 it will deacelerate in presence of electric field in presence of magnetic field the particle would be undeflected in both the cases , then why option 1 is incorrect

Q. What is the magnitude of magnetic field at the point P due to a current carrying wire of length 4 m and having a current of 4 A as shown in the figure? $[{\mu }_0=4\pi \times {10}^{-7}Tm/A]$

1. $10\times {10}^{-8}T$
2. $11\times {10}^{-8}T$
3. $9\times {10}^{-8}T$
4. $5\times {10}^{-8}T$

Q. Magnetic field at point O due to the structure is

1. $\frac{{\mu }_{0}I}{4\pi R}(\frac{\pi }{R}+1)\otimes$
2. $\frac{{\mu }_{0}I}{4\pi R}(\pi +1)\odot$
3. $\frac{{\mu }_{0}I}{2\pi R}(\frac{\pi }{R}+1)\otimes$
4. $\frac{{\mu }_{0}I}{2\pi R}(\pi +1)\odot$

Q.

A compass needle placed just above a wire in which electrons are moving towards the west, will point towards

1. East

2. West

3. North

4. South

Q.

A vertical wire carries a current straight down. To the east of this wire, the magnetic field points:

1. eastwards

2. downwards

3. southwards

4. northwards

Q.

On reversing the direction of current in a wire, the magnetic field produced by it:
(a) gets reversed in direction
(b) increases in strength
(c) decreases in strength
(d) remains unchanged in strength and direction.

Q.

Question 2
The magnetic field in a given region is uniform. Draw a diagram to represent it.

Q.

Question 15
AB is a current carrying conductor in the plane of the paper as shown in Figure. What are the directions of magnetic fields produced by it at points P and Q? Given $r_1>r_2$, where will the strength of the magnetic field be larger?

Q.

(a) Draw a sketch to show the magnetic lines of force due to a current-carrying straight conductor.

(b) Name and state the rule to determine the direction of magnetic field around a straight current-carrying conductor.

Q.

It is established that an electric current through a metallic conductor produces a magnetic field around it. Is there a similar magnetic field produced around a thin beam of moving (i) alpha particles, and (ii) neutrons? Justify your answer.

Q. 1 A current flows through an infinitely long straight wire. The magnetic field produced at a point 1 m away from it is

1. $2\times {10}^{-7}T$
2. $\frac{2}{10}T$
3. $2\times {10}^{-3}T$
4. $2\pi \times {10}^{-6}T$

Q.

What will happen to a compass needle when the compass is placed below a wire with needle parallel to it and a current is made to flow through the wire ? Give a reason to justify your answer.

Q.

A coil of $40\Omega$ resistance has $100$ turns and a radius of $6mm$ is connected to an ammeter of resistance of $160\Omega$. The coil is placed perpendicular to the magnetic field. When the coil is taken out of the field, $32\mu C$ charge flows through it. The intensity of the magnetic field will be

1. $6.55T$

2. $5.66T$

3. $0.655T$

4. $0.566T$

Q. The magnetic field near a long straight wire is given by

1. straight field lines perpendicular to the wire.
2. radial field lines starting from the wire.
3. straight field lines parallel to the wire.
4. concentric circles centered on the wire.

Q. When a coil is rotated in a magnetic field and is connected to a circuit using slip rings, the direction of current in the circuit.

1. is constant
2. changes continuously
3. does not change
4. is not measurable

Q. Two current-conducting wires are hung on a plastic rod. A large current is passed through the two wires in the direction shown.


Statement I: I and II repel each other.
Statement II: I and III repel each other
Statement III: II and III attract each other
Which of the following options is correct regarding this?

1. Statement I and III are correct while statement II is incorrect
2. Statement II and III are correct while statement I is incorrect
3. All the statements are correct
4. All the statements are incorrect

Q. The magnetic field lines around a straight current carrying conductor is in the shape of .

1. concentric circles
2. a circle
3. congruent triangles

Q.

A straight wire lying in a horizontal plane carries a current from north to south.

(a) What will be the direction of magnetic field at a point just underneath it?

(b) Name the law used to arrive at the answer in part (a).

Q.

An electric current of 5 amperes flows through a conductor for 15 seconds. Find the amount of charge that flows.

Q. A long wire is bent into the shape PQRST as shown in the figure with QRS being a semicircle with centre O and radius r. A current I flows through it in the direction $P\to Q\to R\to S\to T$. The net magnetic field at point O is

1. 
   ${\mu }_0[\frac{I}{2\pi r}+\frac{I}{4r}]$
2. 
   ${\mu }_0[\frac{I}{2\pi r}+\frac{I}{2r}]$
3. 
   $\frac{{\mu }_{0}I}{4r}$
4. 
   $\frac{{\mu }_{0}I}{4\pi }$

Q.

How is the magnetic field due to a straight current carrying wire affected if current in the wire is (a) decreased, (b) reversed?

Q. Two identical small conducting sphere are separated of 1m. The sphere originally the same positive charge and the force between them F^°. Half of the charge on one sphere is then moved to other sphere. The force between the sphere is now

Q. What is the force acting on a current carrying wire which is placed in a magnetic field along the direction of the magnetic field?

1. force acting on wire is positive
2. force acting on wire is maximum
3. force acting on wire is zero
4. force acting on wire is negative

Q.

Question 13
A magnetic compass needle is placed in the plane of paper near point A as shown in Figure. In which plane should a straight current carrying conductor be placed so that it passes through A and there is no change in the deflection of the compass? Under what condition is the deflection maximum and why?