WorksheetsMoving Charges and Magnetic effect
Total questions: 35
Worksheet time: 31mins
A straight wire of diameter 0.5 mm carrying a current of 1 A is replaced by another wire of 1 mm diameter carrying same current. The strength of the magnetic field at the same point is:
twice the earlier value
half of the earlier value
quarter of the earlir value
no change
The magnetic field at 10 cm from the axis of a straight wire carrying some current is 10-⁵ T. The current through the wire will be:
25.1 A
12.6 A
5 A
0.4 A
At a distance of 10 cm from a long straight wire carrying current, the magnetic field is 0.04 Tesla. At the distance of 40 cm, the magnetic field will be:
0.01 T
0.02 T
0.08 T
0.16 T
An electric current passes through a long straight wire. At a distance 5 cm from the wire, the magnetic field is B. The field at 20 cm from the wire should be:
2B
B/4
B/2
B
The field intensity due to current I flowing through a straight long wire is proportional to:
I
I²
SQUARE ROOT OF I
1/I
A long wire is carrying current of i ampere. If at a distance r the magnetic field is 0.4 tesla then magnetic field at a distance 2r will be:
0.2 T
0.8 T
0.1 T
1.6 T
A particle of mass 0.5 gm and charge 2.5 × 10⁻⁸ coulomb is moving with velocity 6 × 10⁴ m/s, what should be the value of magnetic field acting on it, so that the particle is able to move in a straight line:
0.327 weber/m²
3.27 weber/m²
32.7 weber/m²
this is not possible
If the magnetic field at a distance of 2 cm from an infinite current carrying wire is 10⁻⁶ weber/m², then the value of current in ampere will be:
1
0.1
10
none of the above
The intensity of magnetic field at a point situated at a distance r close to a long straight current carrying wire is B. The intensity of field at a distance r/2 from the wire will be:
B/2
B/4
2B
4B
The incorrect statement of the following is:
Work done on a moving charge in a magnetic field is zero
the kinetic energy of a moving charge in magnetic field is conserved
magnetic field is not produced due to electron moving in a straight line
kinetic energy of a moving charge in an electric field changes
Two free parallel wires carrying currents in opposite direction
Attract each other
Repel each other
Neither attract nor repel
Get rotated to be perpendicular to each other
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 . The magnetic dipole moment of the coil is
0.15 Am²
0.3 Am²
0.45 Am²
0.6 Am²
A conducting circular loop of radius r carries a constant current I. It is placed in a uniform magnetic field B , such that B is perpendicular to the plane of the loop. The magnetic force acting on the loop is
IrB
2IrB
zero
IrB/2
A current carrying loop is placed in a uniform magnetic field. The torque acting on it does not depend upon
Shape of the loop
Area of the loop
Value of the current
Magnetic field
To make the field radial in a moving coil galvanometer
The number of turns in the coil is increased
Magnet is taken in the form of horse-shoe
Poles are cylindrically cut
Coil is wounded on aluminium frame
A current carrying rectangular coil is placed in a uniform magnetic field. In which orientation, the coil will not tend to rotate
The magnetic field is parallel to the plane of the coil
The magnetic field is perpendicular to the plane of the coil
The magnetic field is at 45⁰ with the plane of the coil
Always in any orientation
A long solenoid has a radius r and number of turns per unit length is n. If it carries a current I, then the magnetic field on its axis is directly proportional to
r n I
r n² I
n I
r² n I
A long toroid is formed by winding 20 turns/cm. The current necessary to produce a magnetic field of 20 millitesla inside the solenoid will be approximately
7.9 A
4 A
2 A
1 A
A straight wire of length 2(3.14)² metre is carrying a current of 2A and the magnetic field due to it is measured at a point distant 1 cm from it. If the wire is to be bent into a circle and is to carry the same current as before, the ratio of the magnetic field at its centre to that obtained in the first case would be
50 : 1
1 : 50
100 : 1
1 : 100
Tesla is the unit of
Magnetic flux
Electric field
Magnetic field
Electric flux
PQRS is a square loop made of uniform conducting wire the current enters the loop at P and leaves at S. Then the magnetic field will be
Not zero at the centre of the loop
Zero at the centre of loop
Zero at all points inside the loop
Zero at all points outside of the loop
A proton moving with a constant velocity passes through a region of space without any change in its velocity. If E and B represent the electric and magnetic fields respectively, then this region of space may have
E = 0, B = 0
E = 0, B is not zero
E is not zero, B is not zero
All of the above
A proton (mass m and charge +e) and an alpha particle (mass 4m and charge +2e) are projected with the same kinetic energy at right angles to the uniform magnetic field. Which one of the following statements will be true
The alpha particle will be bent in a circular path with a small radius that for the proton
The radius of the path of the alpha particle will be greater than that of the proton
The alpha particle and the proton will be bent in a circular path with the same radius
The alpha particle and the proton will go through the field in a straight line
A charged particle moving in a magnetic field experiences a resultant force
In the direction of field
In the direction opposite to that field
In the direction perpendicular to both the field and its velocity
None of the above
Particles having positive charges occasionally come with high velocity from the sky towards the earth. On account of the magnetic field of earth, they would be deflected towards the
North
South
East
West
A uniform magnetic field acts at right angles to the direction of motion of electrons. As a result, the electron moves in a circular path of radius 2 cm. If the speed of the electrons is doubled, then the radius of the circular path will be
2.0 cm
0.5 cm
4.0 cm
1.0 cm
The sensitiveness of a moving coil galvanometer can be increased by decreasing
The number of turns in the coil
The area of the coil
The magnetic field
The couple per unit twist of the suspension
A rectangular coil 20 cm x 20 cm has 100 turns and carries a current of 1 A. It is placed in a uniform magnetic field B =0.5 T with the direction of magnetic field parallel to the plane of the coil. The magnitude of the torque required to hold this coil in this position is
Zero
200 N-m
2 N-m
10 N-m
If a current is passed in a spring, it
Gets compressed
Gets expanded
Oscillates
Remains unchanged
Three long, straight and parallel wires carrying currents are arranged as shown in figure. The force experienced by 10 cm length of wire Q is
1.4 x 10⁻⁴ towards the right
1.4 x 10⁻⁴ towards the left
2.6 x 10⁻⁴ to the right
2.6 x 10⁻⁴
What is shape of magnet in moving coil galvanometer to make the radial magnetic field
Concave
Rectangular
Convex
None of these
A small cylindrical soft iron piece is kept in a galvanometer so that
A radial uniform magnetic field is produced
A uniform magnetic field is produced
There is a steady deflection of the coil
All of these
Two galvanometers A and B require 3mA and 5mA respectively to produce the same deflection of 10 divisions. Then
A is more sensitive than B
B is more sensitive than A
A and B are equally sensitive
Sensitiveness of B is 5/3 times that of A
In which of the following cases the magnetic field is not produced when electric charge:
is moving with acceleration.
is moving with retardation.
is moving with uniform velocity.
is at rest.
When current is passed through a conductor then surrounding the conductor is generated:
an electric field
a gravitational field.
a magnetic field
no field.
