WorksheetsGrade 12- Moving Charges and Magnetism
Total questions: 43
Worksheet time: 22mins
What will be the direction of the force on the electron in the given figure?
Towards left
Towards right
Upwards
Downwards
What is the magnetic field at point P due to the given circular current carrying coil?
(μo I)/(4√2 r) along OP
(μo I)/2r along OP
(μo I)/(4√2 r) along PO
(μo I)/2r along PO
Resultant magnetic field at centre O will be
(μo I)/2r
(μo I)/4r
(μo I)/r
Zero
Which of the following can produce a magnetic field?
(a) A static charge
(ii) A moving charge
(iii) An accelerating mass particle
(iv) An oscillating body
Magnetic field at the centre of a coil is B. What will be new magnetic field if the current, no. of turns and radius of the coil all are doubled?
(1) B
(2) 2B
(3) 4B
(4) B/2
The direction of force on the wire will be :
upwards
downwards
towards left
towards right
The magnetic field due to the current carrying arc at point O is
(μ0I θ)/(2πr)
(μ0I θ)/(4πr)
(μ0I θ)/(4r)
zero
In Biot – Savart law the direction of dB is always
along r
Along dl
perpendicular to r
Perpendicular to both dl and r
Work done by the magnetic force in moving the charge particle of the circular path is :
(𝑞^2𝐵^2𝑟^2)/2𝜋𝑟
2πr*qvB
zero
(mv^2)/r* 2πr
In a certain region of space, electric field
E and magnetic field
B are perpendicular to each other. An electron enters perpendicularly to both the fields and moves undeflected. The velocity of electron is
E/B
B/E
E x B
E.B
A deuteron of kinetic energy 50 keV is describing a circular orbits of radius 0.5 m in a plane perpendicular to the magnetic field B. The kinetic energy of the proton that describes a circular orbit of same radius and inside same B is
25 keV
50 keV
200 keV
100 keV
A rectangular coil ABCD is placed near a long straight current carrying straight wire as shown. What is the net force on the rectangular coil?
25 x 10-7 N towards the wire
25 x 10-7 N away from the wire
35 x 10-7 N, towards the wire
35 x 10-7 N, away from the wire
To convert a moving coil galvanometer into on ammeter of given range, we must connect:
A suitable low resistance in series
A suitable low resistance in parallel
A suitable high resistance in parallel
A suitable high resistance in series
Current sensitivity of a galvanometer can be increased by decreasing :
Magnetic field B
number of turns N
torsional constant K
Area A
Two wires of same length are shaped into a square and a circle if they carry same current, ratio of magnetic moment is :
2 : pi
pi: 2
pi: 4
4:pi
An electric current passes through a long straight copper wire. At a distance 5 cm from the straight wire, the magnetic field is B. The magnetic field at 20 cm from the straight wire would be
B/6
B/4
B/3
B/2
Currents of 10 A and 2 A are flowing in opposite directions through two parallel wires A and B respectively. If the wire A is infinitely long and wire B is 2 m long, then force on wire B which is situated at 10 cm from A, is
8 x 10 ^ -5 N
6 x 10 ^-5 N
4 x 10 ^ -5 N
2 X 10 ^ -5 N
A wire in the form of a circular loop, of one turn carrying a current, produces magnetic induction B at the centre. If the same wire is looped into a coil of two turns and carries the same current, the new value of magnetic induction at the centre is
B
2B
4B
8B
A 100 turns coil shown in the figure carries a current of 2 A in a magnetic field of .2Wbm2 The torque acting on the coil is
0.32 N-m tending to rotate the side AC into the page
0.32 N-m tending to rotate the side AC out of the page
0.64 N-m tending to rotate the side AC into the page
0.64 N-m tending to rotate the side AC out of the page
Current sensitivity of a galvanometer can be increased by decreasing (a) .
An electron passes undeflected when passes through a region with electric and magnetic fields. When electric field is switched off its path will change to (a) .
A linear conductor carrying current if placed parallel to the direction of magnetic field, then it experiences ---------------- force.
(a)
A linear conductor carrying current if placed parallel to the direction of magnetic field, then it experiences ---------------- force.
(a)
Biot-Savart law indicates that the moving electrons (velocity v) produce a magnetic field B such that
B ⊥ v.
B || v.
it obeys inverse cube law.
it is along the line joining the electron and point of observation.
A circular coil of radius 4 cm and of 20 turns carries a current of 3 amperes. It is placed in a magnetic field of intensity of 0.5 weber /m². The magnetic dipole moment of the coil is
0.15 ampere-m²
0.3 ampere-m²
0.45 ampere-m²
0.6 ampere-m²
The maximum current that can be measured by a galvanometer of resistance 40 Ω is 10 mA. It is converted into voltmeter that can read upto 50 V. The resistance to be connected in the series with the galvanometer is
2010 Ω
4050 Ω
5040 Ω
4960 Ω
If the beams of electrons and protons move parallel to each other in the same direction, then they
attract each other.
repel each other.
no relation.
neither attract nor repel.
In a circular coil of radius r, the magnetic field at the centre is proportional to
r²
r
1/r
2r
When a magnetic compass needle is carried nearby to a straight wire carrying current, then
(I) the straight wire cause a noticeable deflection in the compass needle.
(II) the alignment of the needle is tangential to an imaginary circle with straight wire as its centre and has a plane perpendicular to the wire
(I) is correct
(II) is correct
both (I) and (II) are correct
neither (I) nor (II) is correct
Two a-particles have the ratio of their velocities as 3 : 2 on entering the field. If they move in different circular paths, then the ratio of the radii of their paths is
2 : 3
3 : 2
9 : 4
4 : 9
A small object with a charge of 𝑞 = +3.0 μ𝐶 and a mass 𝑚 = 2.0 × 10-6 𝑘𝑔 enters a magnetic field of magnitude 𝐵 = 0.20 𝑇 directed into the page, as shown in the figure below. If the speed of the object is 1000 𝑚/𝑠, the object’s acceleration at the moment it enters the field is most nearly ______.
zero because the velocity is perpendicular to the magnetic field
300 m/s2 toward the bottom of the page
300 m/s2 toward the top of the page
600 m/s2 toward the bottom of the page
600 m/s2 toward the top of the page
A particle carrying a charge of +e travels in a circular path in a uniform magnetic field. If instead the particle carried a charge of +2e, the radius of the circular path would have been ____.
twice the original radius
four times the original radius
the same as the original radius
one-half the original radius
one-fourth the original radius
A proton travels at a speed of 5.0 × 107 𝑚/𝑠 through a 1.0 𝑇 magnetic field. What is the magnitude of the magnetic force which acts on the proton if the angle between the proton's velocity and the magnetic field vector is 30°?
2.0×10-14 𝑁
4.0×10-14 𝑁
2.0×10-12 𝑁
4.0×10-12 𝑁
6.0×10-12 𝑁
A charged particle of mass 𝑚 is exposed to a constant magnetic field of magnitude 𝐵 and directed out of the page, in which the particle moves in a clockwise circle of radius 𝑅 with a speed 𝑣, as shown below.
In a separate experiment, the same particle is traveling with a speed 2𝑣 in a constant magnetic field of the same magnitude 𝐵, now directed into the page. Which of the following statements is true?
Now the particle travels in a clockwise circle of radius R
Now the particle travels in a counterclockwise circle of radius R
Now the particle travels in a counterclockwise circle of radius 2R
Now the particle travels in a clockwise circle of radius R/2
Now the particle travels in a counterclockwise circle of radius R/2
Uniform magnetic and electric fields exist between the two oppositely charged parallel plates shown in the figure below. An electron travels horizontally between the plates. Assuming gravitational effects to be negligible, which of the following diagrams shows a combination of electric and magnetic field directions that will allow the electron to travel un-deflected?
Four small particles are seen moving through an area with the magnetic field going out of the page. Which of the following statements is consistent with the diagram?
All the particles are positively charges but have different mass
All the particles have same mass, but different charges
Two particles are positive while one is negative
Two particles are negative while one is positive
You can only ascertain that all are charged
A particle of charge 𝑞 and mass 𝑚 is moving through a region of space at right angles to an electric field and a magnetic field, where the crossed fields produce a zero net force on the charge. If the speed of the charge is doubled, which of the following will again produce a zero net force on the charge?
I. Reducing the electric field to 𝐸/2
II. Increasing the electric field to 4𝐸
III. Reducing the magnetic field to 𝐵/2
IV. Increasing the magnetic field to 2𝐵
I only
II only
III only
II and III only
I and IV only
How can u convert MCG to voltmeter
High resistance parallel
High resistance series
Low resistance parallel
High resistance parallel
What is the principle of MCG
Current carrying coil in an electric field experiences a force
Current carrying coil in magnetic field experiences no force
Current carrying conductor in magnetic field experiences a force
Current carrying conductor in an electric field produces no force
A galvanometer has a resistance of 10 ohm and meter shows full scale deflection for a current of 4 mA. How will u convert the meter into an ammeter of range 0 to 6 A?
10 milli ohm
6.67 ohm
7.5 ohm
6.67 milli ohm
____________ is a low resistance connected in parallel to convert MCG to ___________
(a)
Diagrams of electric fields and magnetic fields often look similar. What is an important difference between electric field lines and magnetic field lines?
Electric field lines always point away from the object generating the field, while magnetic lines always point toward it.
Electric field lines are close together where the electric field is strong, but magnetic lines are close where the magnetic field is weak.
Electric field lines start and end on charges, while magnetic field lines form closed-loop paths to and from the poles.
Magnetic field lines cannot cross, while electric field lines can
How could you make a stronger electromagnet?
more coils of wire
add an iron core
more current in the wire
all three
