Advertisements
Advertisements
Question
PQ is a long straight conductor carrying a current of 3A as shown in Figure below. An electron moves with a velocity of 2 x 107 ms-1 parallel to it. Find the force acting on the electron.
Solution
q = 1.6 × 10-19 C, i=3 A, r = 0. 6 m
v = 2 x 107 ms-1
θ = 90°
`bar(B) = 10^-7 xx (2xx3)/0.6`
∴ Force on electron, \[\overrightarrow{F }\] = q v B sin θ
\[\overrightarrow{F }\] = 1.6 x 10-19 x 2 x 107 x 107. `6/0.6`
\[\overrightarrow{F }\]= 3.2 x 10-18 N
APPEARS IN
RELATED QUESTIONS
Two long, straight, parallel conductors carry steady currents, I1 and I2, separated by a distance d. If the currents are flowing in the same direction, show how the magnetic field set up in one produces an attractive force on the other? Obtain the expression for this force. Hence, define one ampere.
Deduce the expression for the magnetic field at a point on the axis of a current carrying circular loop of radius ‘R’ distant ‘x’ from the centre. Hence, write the magnetic field at the centre of a loop.
The electric current flowing in a wire in the direction from B to A is decreasing. Find out the direction of the induced current in the metallic loop kept above the wire as shown.
A rod of length l is moved horizontally with a uniform velocity 'v' in a direction perpendicular to its length through a region in which a uniform magnetic field is acting vertically downward. Derive the expression for the emf induced across the ends of the rod.
A circular coil of wire consisting of 100 turns, each of radius 8.0 cm carries a current of 0.40 A. What is the magnitude of the magnetic field B at the centre of the coil?
Obtain an expression for magnetic flux density B at the centre of a circular coil of radius R, having N turns and carrying a current I
Two wires carrying equal currents i each, are placed perpendicular to each other, just avoiding a contact. If one wire is held fixed and the other is free to move under magnetic forces, what kind of motion will result?
A charged particle is moved along a magnetic field line. The magnetic force on the particle is
Each of the batteries shown in figure has an emf equal to 5 V. Show that the magnetic field B at the point P is zero for any set of values of the resistances.
State whether the following statement is true or false:
Magnetic poles exist in pairs.
A particle with charge q moves with a velocity v in a direction perpendicular to the directions of uniform electric and magnetic fields, E and B respectively, which are mutually perpendicular to each other. Which one of the following gives the condition for which the particle moves undeflected in its original trajectory?
Which one of the following is a correct statement about magnetic forces?
In the product `vec"F" = "q" (vec"υ" xx vec"B")`
= `"q" vec"υ" xx ("B"hat"i" +"B"hat"j" + "B"_0hat"k")`
For q = 1 and `vec"υ" = 2hat"i" + 4hat"j" + 6hat"k"` and
`vec"F" = 4hat"i" - 20hat"j" + 12hat"k"`
What will be the complete expression for `vec"B"`?
An infinitely long straight conductor carries a current of 5 A as shown. An electron is moving with a speed of 105 m/s parallel to the conductor. The perpendicular distance between the electron and the conductor is 20 cm at an instant. Calculate the magnitude of the force experienced by the electron at that instant.
In the product
`overset(->)("F") = "q"(overset(->)(υ) xx overset(->)("B"))`
= `"q"overset(->)(υ) xx ("B"overset(^)("i") + "B" overset(^)("j") + "B"_0overset(^)("k"))`
For q = 1 and `overset(->)(υ) = 2overset(^)("i") + 4overset(^)("j") + 6overset(^)("k")` and
`overset(->)("F") = 4overset(^)("i") - 20overset(^)("j") + 12overset(^)("k")`
What will be the complete expression for `overset(->)("B")`?
A cubical region of space is filled with some uniform electric and magnetic fields. An electron enters the cube across one of its faces with velocity v and a positron enters via opposite face with velocity – v. At this instant ______.
- the electric forces on both the particles cause identical accelerations.
- the magnetic forces on both the particles cause equal accelerations.
- both particles gain or loose energy at the same rate.
- the motion of the centre of mass (CM) is determined by B alone.
A charged particle would continue to move with a constant velocity in a region wherein ______.
- E = 0, B ≠ 0.
- E ≠ 0, B ≠ 0.
- E ≠ 0, B = 0.
- E = 0, B = 0.
With a neat labelled diagram, explain cyclotron motion and cyclotron formula.
