Q.1
A circular coil of radius 20cm having 50 turns carries a current of 2A. The magnetic moment of the coil is
  • a) 0.4 π A-m2
  • b) 4π A-m2
  • c)40 π A-m2
  • d)400 π A-m2
Q.2
Magnetic field due to a current carrying torodal solenoid is independent of
  • a)its number of turns
  • b) current
  • c)radius
  • d)none of the above
Q.3
What is the magnetic field in the empty space enclosed by the toroidal solenoid of radius R?
  • a) infinity
  • b) µoI /(4πR)
  • c)µoπI /(4πR)
  • d)zero
Q.4
A wire bent in the form of right angled triangle ABC as shown in figure carries a current 1 A. It is placed in the region of uniform magnetic field B=0.2T as shown in figure. IF AC=1m, the net force on the wire is
ch-16_que_no-196_img_no1.png
  • a) 1.73 N
  • b) 3.46 N
  • c) 2.732 N
  • d) Zero
Q.5
If a long copper rod carries a direct current the magnetic field associated with current will be
  • a)inside the rod only
  • b) outside the rod only
  • c)both inside and outside the rod
  • d)neither inside nor outside the rod
Q.6
As shown in figure rectangular coil of cross-section area A placed in uniform magnetic field B directed along Z-axis. The torque on the coil is
ch-16_que_no-198_img_no1.png
  • a) ABI along +Ve Y-axis
  • b) ABI along -ve Y-axis
  • c)ABI along +VE X-axis
  • d)zero
Q.7
Two parallel wires each of 0.5 m in length atre at distance 1 metre from each other. If current through each wire is 1 amp, then force between the two wires is
  • a) 10-7 N
  • b) 0.5 N
  • c)107 N
  • d)5 ×1014 N
Q.8
An electron of mass m is accelerated through a potential difference of V and then it enters a magnetic field of induction B normal to the lines. the radius of circular path is
  • a)
    ch-16_qn-200choice_img_no1.png
  • b)
    ch-16_qn-200choice_img_no2.png
  • c)
    ch-16_qn-200choice_img_no3.png
  • d)
    ch-16_qn-200choice_img_no4.png
Q.9
An electron moves in a circular arc of radius 10 m at a constant speed of 2×107 m/s with its plane of motion normal to the magnetic flux density of 10-5T. What value does, from this set of figure, give for the specific charge of the electron?
  • a)2 × 102 C/kg
  • b) 2 ×105 C/kg
  • c)5 ×106 C/kg
  • d)2 ×1011 C/kg
Q.10
A battery is connected between to points A and B on the circumference of a uniform conducting ring of radius r and resistance R. One of the arc AB of the ring subtends angle θ at the centre. The value of the magnetic induction at the centre due to the current in the ring is
  • a) Proportional to 2( 180° - θ)
  • b) inversely proportional to r
  • c)zero , only if θ=180°
  • d)zero for all values of θ
Q.11
If a proton is projected in a direction perpendicular to a uniform magnetic field with velocity v and an electron is projected along the line of force, what will happen to proton and electron?
  • a) the electron will travel along a circle with constant speed and the proton will move along a straight line
  • b) proton will move in a circle with constant speed and there will be no effect on the motion of electron
  • c)there will not be any effect on the motion of electron and proton
  • d)the electron and proton both will follow the path of a parabola
Q.12
An electron accelerated through a potential difference of V passes through a magnetic field experiences a force F. If the accelerating potential is increased to 2V, the electron in the same magnetic field will experience force
  • a) F
  • b) F/2
  • c) √2 F
  • d) 2F
Q.13
At a distance of 10cm from long straight wire, carrying current, the magnetic field is 0.04 tesla. At the distance of 40 cm, the magnetic field will be
  • a)0.01 T
  • b) 0.02T
  • c)0.08 T
  • d)0.16 T
Q.14
A circular coil of radius 4 cm having 20 turns carries a current of 3A. It is placed in a magnetic field of intensity 0.5 weber/mThe magnetic dipole moment of coil is
  • c)0.45 amp m2
  • a) 0.15 amp × m²
  • b) 0.30 amp × m²
  • d)0.60 amp × m²
Q.15
If a particle of charge 10-12 C moving along the x-direction with velocity 105 m/s experiences a force of 10-10 N in y-direction due to magnetic field, then the minimum magnetic field is
  • a) 6.26 × 103 tesla in -direction
  • b) 10-15 tesla in z- direction
  • c)103 tesla in z-direction
  • d)10-3 tesla in z-direction
Q.16
A wire of 2m is bent in the form of a circular loop. The magnetic moment of the loop when 1A current flows through it is ......Am2.
  • a) 2π
  • b) π/2
  • c) π/4
  • d) 1/π
Q.17
When current is passed through a circular wire prepared from long conducting wire, magnetic field produced at its centre is B. Now loop having two turns in prepared from the same wire and the same current is passed through it. The magnetic field at its centre will be
  • a)B/4
  • b) B/2
  • c)4B
  • d)2B
Q.18
Electric current "I" flows through a hexagonal loop of side 'a'. Magnetic field ar its centre is
  • a)
    ch-16_qn-210choice_img_no1.png
  • b)
    ch-16_qn-210choice_img_no2.png
  • c)
    ch-16_qn-210choice_img_no3.png
  • d)
    ch-16_qn-210choice_img_no4.png
Q.19
Two particles of mass m and charge q are attached with two ends, one with each end, of rod length 2r. The rod is rotated with angular speed ω about its mid point. The ratio of magnetic moment produced and total angular momentum of these particles to ....
  • a) q/2m
  • b) q/m
  • c)2q/m
  • d)q/πm
Q.20
Two very long conducting parallel wires are separated by a distance d from each other and the same current I is passing through them in mutually opposite directions. A particle of charge q passes through a point which is at distance d/2 from both wires, with velocity v, perpendicularly to the plane formed by the wires. Resulting magnetic force acting on this particle is ...
  • a)
    ch-16_qn-212choice_img_no1.png
  • b)
    ch-16_qn-212choice_img_no2.png
  • c)
    ch-16_qn-212choice_img_no3.png
  • d) zero
Q.21
A stationary charged particle does not experience any net electromagnetic force, then ...
  • a)magnetic field may be zero or non-zero
  • b) magnetic field must be zero
  • c)electric field may be zero or non zero
  • d)electric field must be zero
Q.22
Electric current I flows through the wall of conducting pipe of infinite length, in a direction parallel to its length, then...
  • a) magnetic field is non-zero and equal at all points in inner region of the pipe
  • b) magnetic field is zero at all points in the inner region of pipe
  • c)electric field is zero only on the axis of the pipe
  • d)magnetic field is different at different points in the inner region of the pipe
Q.23
No magnetic force acts if ... is stationary
  • a) an electric dipole
  • b) magnetic dipole
  • c)a coil carrying current
  • d)a straight conductor carrying current
Q.24
A very long solenoid of length L has n layers. There are N turns in each layer. Diameter of the solenoid is D and current I passes through it, then magnetic field;d at the centre of solenoid is
  • a) directly proportional to D
  • b) inversely proportional to D
  • c) independent of D
  • d) directly proportional to L
Q.25
There are 200 turns per centimeter of avery long solenoid. If 2.5 A current passes through it, then the magnetic field at its centre on the axis is ... T
  • a)3.14 × 10⁻²
  • b) 6.28 × 10⁻²
  • c)9.42 × 10⁻²
  • d)12.56 × 10⁻²
Q.26
If a proton is moving with velocity 3 ×105 m/s at an angle of 30° in a magnetic field 0.3 T, then the radius of curvature of its trajectory will be .. [ for proton e/m=108 C/kg]
  • a) 0.5 cm
  • b) 0.02 cm
  • c)1.25 cm
  • d)2.0 cm
Q.27
A moving charge gains energy due to ....
  • a) electric field
  • b) magnetic field
  • c)both these fields
  • d)none of these fields
Q.28
In a region E and B represent electric and magnetic field respectively. If an electron moves with constant velocity (v) through that region, then the region may not have ....
  • a)E=0, B=0
  • b) E=0 , B ≠ 0
  • c)E ≠ 0, B=0
  • d)E ≠ 0 , B ≠ 0
Q.29
Two beams of protons moving parallel and in the same direction, will
  • a) Attract each other
  • b) exerts no force on each other
  • c)repel each other
  • d)can't say anything
Q.30
Unit of permeability is ........
  • a) (T - A)/m
  • b) (T-m)/A
  • c)(m-A)/T
  • d)none of them
0 h : 0 m : 1 s