MCQGeeks
0 : 0 : 1
CBSE
JEE
NTSE
NEET
English
UK Quiz
Quiz
Driving Test
Practice
Games
NEET
Physics NEET MCQ
Magnetism Mcq
Quiz 10
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Q.1
The dimensional representation for magnetic flux density is .....
0%
a)MLT-2
0%
b) MLT-2A-1
0%
c)MT-2A-1
0%
d)MLT-2A-2
Explanation
Answer: (c)
Q.2
Name the physical quantity which has the same dimension as √(K/MB) here K is moment of inertia
0%
a) frequency
0%
b) time
0%
c)speed
0%
d)distance
Explanation
Answer: (b)
Q.3
When all the molecular dipoles in a magnet arrange themselves in the direction of magnetic field lines, the condition is called
0%
a) permitivity
0%
b) retentivity
0%
c)coercivity
0%
d)saturation
Explanation
Answer:(d)
Q.4
Dimension of electric flux / magnetic flux are ...
0%
a) L T-1
0%
b) T-1 L-1
0%
c) L3 T2A-2
0%
d) MoLoTo
Explanation
Flux describes any effect that appears to pass or travel (whether it actually moves or not) through a surface. flux is defined as the rate of flow of a property per unit area, which has the dimensions [quantity]·[time]-1·[area]-1Answer: (b)
Q.5
Two magnetic dipoles of magnetic moment 1.0 Am2 each are placed at a separation of 2m with their axis perpendicular to each other. The resultant magnetic field at a point midway between dipoles is .....
0%
a)√2 × 10-5
0%
b) √5 × 10-5
0%
c)2 × 10-5
0%
d)3 × 10-5
Explanation
The ratio of to magnetic field is 2:1 and they are perpendicular to each other thus option "b" is correctAnswer: (b)
Q.6
Name the instrument with which we measure the value of induced magnetic moment in a substance
0%
a) galvanometer
0%
b) magnetometer
0%
c)tangent galvanometer
0%
d)none of these instruments
Explanation
Answer: (b)
Q.7
Magnetic field strength due to a short bar magnet on its axial line at a distance X is B. What is its value at the same distance on the equatorial line?
0%
a) B/2
0%
b) B
0%
c)2B
0%
d)4B
Explanation
Answer:(a)
Q.8
Point P and Q are situated on the axis of 2cm long bar magnet at large distance d and 3d from its centre on opposite sides. The ratio of the magnetic field at P and Q will be approximately equal to .....
0%
a) 3 : 1
0%
b) 9 : 1
0%
c) 27 : 1
0%
d) 81 : 1
Explanation
B ∝ 1/ d3 Answer: (c)
Q.9
A magnetic needle vibrates in the vertical plane perpendicular to the magnetic meridian. Its time period is 2 seconds. If the same needle vibrates in the horizontal plane and the time period is again 2 seconds, what is the angle of dip at the place?
0%
a)30°
0%
b) 45°
0%
c)60°
0%
d)None of these
Explanation
this is possible only if vertical and Horizontal component are sameAnswer: (b)
Q.10
If the magnetic flux is represented in Weber, then the unit of magnetic induction will be ... [ GUJCET 2006]
0%
a) Wb/m2
0%
b) Wb × m
0%
c)Wb × m2
0%
d)Wb/m
Explanation
Answer: (a)
Q.11
There are 2.0 × 1024 molecular dipoles in a paramagnetic salt. Each has dipole moment 1.5 ×10-23 A-mFind the maximum ( saturation) magnetization in the specimen [ GUJCET 2008]
0%
a)30 A-m2
0%
b) 20 A-m2
0%
c)50 A-m2
0%
d)200 A-m2
Explanation
Maximum dipole moment per unit volume=NM/V MAximum dipole moment per unit volume=nM=2.0×1024×1.5×10-2Answer: (a)
Q.12
The length of a magnet is large compared to its width and breadth. The time period of its oscillation in a vibration magnetometer is 2s. The magnet is cut along its length into three equal parts and then three parts are placed on each other with their like poles together. The time period of this combination will be ...[ AIEEE 2004]
0%
a) 2 s
0%
b) (2/3) s
0%
ac)2√3 s
0%
d)2/√3 s
Explanation
Moment of inertia of one part When they are place on each other, moment of inertia K"=3(K/27)=K/9 But Magnetic moment will become same as earlier=M Thus time period Answer: (d)
Q.13
Relative permitivity and permeability of material are εr and µr respectively. Which of the following values of these quantifies are allowed for diamagnetic material? [ AIEEE 2009]
0%
a)εr=0.5 µr=0.5
0%
b)εr=1.5 µr=1.5
0%
c)εr=0.5 µr=1.5
0%
d)εr=1.5 µr=0.5
Explanation
Answer:(d)
Q.14
The dimension of magnetic field in M,L,T, and C ( coulomb) is given as .... [ AIEEE 2009]
0%
a) MT-1C-1
0%
b) MT-2C-1
0%
c) MLT-1C-1
0%
d) MT2C-2
Explanation
Using equation F=qvBsinθ Answer: (a)
Q.15
The magnetic moment has dimensions of .... [ AIIMS 2006]
0%
a)LA
0%
b) L2A
0%
c)LT-1A
0%
d)L2T-1A
Explanation
Answer: (b)
Q.16
A solenoid is 1.5 m long and its inner diameter is 4.0cm. It has 3 layers of windings of 1000 turns each and carries a current of 2.0 A. The magnetic flux for a cross-section of the solenoid is nearly.....
0%
a) 4.1 ×10-5 Wb
0%
b) 5.2 ×10-5 Wb
0%
c)6.31 ×10-3 Wb
0%
d)2.5 ×10-7 Wb
Explanation
Number of turns per unit length=(3 × 100) / 1.5=2000 B=µo nI B=4π × 10-7 × 2000 × 2=16π ×1-4and Φ=NBA Area of coil=πr2=π(2×10-2)2=4π×10-4therefore magnetic flux Answer: (c)
Q.17
a coil having 100 turns and area of 0.001m2 is free to rotate about an axis, the coil is placed perpendicular to a magnetic field of 1.0 Wb/mIf the coil is rotated rapidly through an angle of 180°, how much charge will flow through the coil? The resistance of coil is 10Ω [ AFMC 2002]
0%
a) 0.02 C
0%
b) 0.04 C
0%
c)0.08 C
0%
d)0.01 C
Explanation
Use formula Q=N(φ2 - φ1) / R φ1=BAcos 0 and φ2=BAcos 180 Answer:(a)
Q.18
In which direction, would the magnetic field on the axis at a distance Z from the centre of the bar magnet be ( GUJCET 2009]
0%
a) Its direction depends on the magnitude of magnetic moment (M) of the magnet
0%
b) In the perpendicular direction of the magnetic moment (M) of the magnet
0%
c) In the opposite direction of magnetic dipole moment (M) of the magnet
0%
d) In the direction of magnetic dipole moment (M) of the magnet
Explanation
Answer: (d)
Q.19
A bar magnet of length l and magnetic dipolemoment M is bent in the form of an arc as shown infigure. The new magnetic dipole moment will be…[ NEET 2013]
0%
a) M
0%
b) 3M/π
0%
c) 2M/π
0%
d) M/2
Explanation
New distance between the poles r as it form a equilateral triangle New magnetic dipole moment = rm…(i) Now L=πr/3 r=3L/π Substituting r in (i) New Magnetic dipole moment M'= 3mL/π As old magnetic moment M = mL therefore M'=3M/π Answer:(b)
Q.20
Following figures show the arrangement of bar magnets in different configuration. Each magnet has dipole moment m. Which configuration has net magnetic dipole moment?
0%
a)
0%
b)
0%
c)
0%
d)
Explanation
Magnetic moment is from S To N Resultant momentum Cos30 is maximum option ‘c’ Answer:(c)
Q.21
A rectangular coil of length 0.12m and width 0.1mhaving 50 turns of wire is suspended vertically in auniform magnetic field of strength 0.2 Weber/mThe coil carries a current of 2 A. If the plane of thecoil is inclined at an angle of 30° with the directionof the field, the torque required to keep the coil instable equilibrium will be :
0%
a) 0.12 Nm
0%
b) 0.15 Nm
0%
c) 0.20 Nm
0%
d) 0.24 Nm
Explanation
Area of coil A = 0.012 m2 Plane of the coil is inclined at an angle 30°, thus angle between area of coil and magnetic field is 60° Magnetic moment µ=nIA µ=50×2×0.012 =1.2 τ=µBsinθ τ=1.2×0.2×sin60 =0.207 Nm ≈0.2 Nm Answer:(a)
Q.22
A bar magnet is hung by a thin cotton thread in a uniform horizontal magnetic field and is in equilibrium state. The energy required to rotate it by 60° is W. Now the torque required to keep the magnet in this new position is …[NEET II-2016]
0%
a) (√3 W)/2
0%
b) 2W/√3
0%
c) W/√3
0%
d) √3 W
Explanation
τ = PE sin 60° .....(1) W = PE (1 – cos60°) .....(2) From (1) and (2) Answer:(d)
Q.23
If θ1 and θ2 be the apparent angles of dip observed in two vertical planes angles to each other then the true angle of dip θ is given by .. [ NEET 2017]
0%
a) cot2 θ= cot2 θ1 + cot2 θ2
0%
b) tan2 θ= tan2 θ1 + tan2 θ2
0%
c) cot2 θ= cot2 θ1 - cot2 θ2
0%
d) tan2 θ= tan2 θ1 - tan2 θ2
Explanation
Let one plane makes angle of δ1 with magnetic meridian as shown in figure B’ is the magnetic field in plane. Now vertical component of both magnetic meridian and plane is B’ . B’sinθ1= Bsinθ … (i) Now Bcosθcosδ1= B’cos θ1 …(ii) Substituting value of B’ from (i) in (ii) Similarly for other plane which is perpendicular Since δ1 + δ2 = π/2 cos δ2 = cos (π/2 – δ1) = sin δ1 Squaring (iii) and (iv) and adding we get Answer:(a)
Q.24
Two short bar magnets of length 1 cm each have magnetic moments 1.20 Am2 and 1.00 Am2 respectively. They are placed on a horizontal table parallel to each other with their N poles pointing towards the South. They have a common magnetic equator and are separated by a distance of 20.0 cm. The value of the resultant horizontal magnetic induction at the mid - point O of the line joining their centre is close to (Horizontal component of earth′s magnetic induction is 3.6 × 10−5 Wb / m2)
0%
a) 3.6 × 10−5 Wb/m2
0%
b) 2.56 × 10−4 Wb/m2
0%
c) 3.50 × 10−4 Wb/m2
0%
d) 5.80 × 10−4 Wb/m2
Explanation
Both the magnetic will produce magnetic filed in same direction from S to N can be calculated using formula Field produced by both the magnet Earth magnetic filed is also from S to N Thus total = 2.2×10-4 + 0.36×10-4 = 2.56×10-4 Wb/m2 Answer:(b)
0 h : 0 m : 1 s
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Report Question
×
What's an issue?
Question is wrong
Answer is wrong
Other Reason
Want to elaborate a bit more? (optional)
Support mcqgeeks.com by disabling your adblocker.
×
Please disable the adBlock and continue.
Thank you.
Reload page