MCQGeeks
0 : 0 : 1
CBSE
JEE
NTSE
NEET
English
UK Quiz
Quiz
Driving Test
Practice
Games
NEET
Physics NEET MCQ
Magnetic Effects Of Current 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
25
26
27
28
29
30
Q.1
A current I=1 A flowing through an infinitely long wire P1 divides between two long wires P2 and P3 at junction C as shown in figure. The magnitude of magnetic field at point O due to wire is .......
0%
a) 10-7 T
0%
b) 5 × 10-7 T
0%
c) 10-6 T
0%
d) 0
Explanation
Answer: (d)
Q.2
As shown in figure, current I flows through a long conducting wire bent at right angles. The magnetic field at point P on the right bisector of the angle at a distance 'r' from O is .....
0%
a)
0%
b)
0%
c)
0%
d)
Explanation
B=B1 + B2 as B1=B2=2B1 Now x=√2Answer: (a)
Q.3
If current is doubled, the deflection is also doubled in .....
0%
a) a tangent galvanometer
0%
b) a moving coil galvanometer
0%
c)both (a) and (b)
0%
d)none of these
Explanation
for moving coil galvanometer Φk=nIAB Φ ∝ I Answer: (b)
Q.4
Two wires of same length are shaped into a square and a circle. If they carry same current, ratio of the magnetic moments is ......
0%
a) 2 : π
0%
b) π : 2
0%
c)π : 4
0%
d)4 : π
Explanation
Length of square=L/4 Area of square A=L2 / 16, radius of circle=L/2π Area A'=of circle=L2 / 4π M1 / M2=IA/IA'=π/4 Answer:(c)
Q.5
An electron is projected along the axis of a circular conductor carrying some current. Electron will experience force .......
0%
a) along the axis
0%
b) perpendicular to axis
0%
c) at an angle of 4° with axis
0%
d) no force experienced
Explanation
Velocity of electron and B have same line of actions Answer: (d)
Q.6
A long starlight wire carrying a current of 30A is placed in an external uniform magnetic field of induction 4 × 10-4 T. The magnetic field is acting parallel to the direction of current. The magnitude of the resultant magnetic induction in tesla at a point 2cm away from wire is .....
0%
a)10-4
0%
b) 3 × 10-4
0%
c)5 × 10-4
0%
d)6 × 10-4
Explanation
MAgnetic induction because of wire B=µoI/ 2πr=3 × 10-4 T External magnetic field is perpendicular to magnetic field produced by wire Resultant magnetic field Answer: (c)
Q.7
A circular coil of radius R carries an electric current. the magnetic field due to the coil at a point on the axis of the coil located at a distance r from the centre of the coil such that r >> R, varies as .....
0%
a) 1/r
0%
b) 1 / r 3/2
0%
c)1 / r 2
0%
d)1 / r 3
Explanation
Answer: (d)
Q.8
A current flows in a conductor from east to west. the direction of the magnetic field at a point above the conductor is .....
0%
a) towards east
0%
b) towards west
0%
c)towards north
0%
d)towards south
Explanation
Answer:(c)
Q.9
A horizontal long straight wire carries 10 A DC current. An electron travels perpendicular to the horizontal plane of this wire at a distance of 0.1m with velocity 5×106 m/s. Force acting on electron due to the current in wire is ....N
0%
a) zero
0%
b) 0.6 ×10-17
0%
c) 1.6 ×10-17
0%
d) 2.2 × 10-17
Explanation
Answer: (a)
Q.10
A 1 metre long wire at right angle to the magnetic field. A force of 1kg weight is acting on it in a magnetic field of 0.98 Tesla. The current flowing in it will be ....
0%
a)100 A
0%
b) 10A
0%
c)1A
0%
d)zero
Explanation
Answer: (b)
Q.11
Weber × ampere per metre is equal to .....
0%
a) joule
0%
b) newton
0%
c)henry
0%
d)watt
Explanation
Answer: (b)
Q.12
A current carrying loop is placed in a uniform magnetic field. The torque acting on it does not depend upon
0%
a) shape of loop
0%
b) area of loop
0%
c)value of the current
0%
d)magnetic field
Explanation
Answer:(a)
Q.13
An electron and a proton enters a magnetic field perpendicularly. Both have same kinetic energy. Which of the following is true?
0%
a) Trajectory of electron is less curved
0%
b) trajectory of proton is less covered
0%
c) both trajectory are equally curved
0%
d) both move on straight line path
Explanation
r=mv/qB But K.e=P2 / 2m p=√(2mK) as charge and kinetic energy in both case is same r ∝ √m Thus radius of proton will be more . Now more the radius, less is the curvature of a circle Answer: (b)
Q.14
An electron is traveling in horizontally towards east. A magnetic field in a vertically downward direction exerts a force on the electron.....
0%
a)eastwards
0%
b) westwards
0%
c)northwards
0%
d)southwards
Explanation
Answer: (d)
Q.15
If current is passed in a spring, it .....
0%
a) gets compressed
0%
b) gets expanded
0%
c)oscillates
0%
d)remains unchanged
Explanation
Each turn behaves as magnet and unlike poles are facing each otherAnswer: (a)
Q.16
A charge q coulomb moves in a circle at n revolutions per second and radius of the circle is r metre, then magnetic field at the centre of the circle is ....
0%
a)
0%
b)
0%
c)
0%
d)
Explanation
Answer:(c)
Q.17
If velocity of an electron is (2i + 3j) m/s enters in the magnetic field of 4kT then .......
0%
a) it will move in the opposite direction of the magnetic field
0%
b) it will move in the direction of the magnetic field
0%
c) its speed will change
0%
d) direction of velocity will change
Explanation
charge performs circular motion hence direction of velocity changes Answer: (d)
Q.18
A current loop ABCD is held fixed on the plane of paper as shown in figure. the arcs BC ( radius=b) and DA ( radius=a) of the loop are by two wires AB and CD. A steady current I is flowing in the loop. Angle made by AB and CD at the origin O is 30°. Another straight thin wire with steady current I1 flowing out of the plane of the paper is kept at origin. The magnitude of magnetic field (B) due to the loop ABCD at the origin O is .... [ AIEEE 2008]
0%
a)
0%
b) zero
0%
c)
0%
d)
Explanation
Magnetic field because of arc BC and DA respectively are Answer: (c)
Q.19
Due to the presence of current I1 in question 289 ....
0%
a) force on loop is
0%
b) The force on AB and DC are zero
0%
c)the force on AD and BC are zero
0%
d) force on loop
Explanation
Magnetic field due to current I1 and current in element are in the same directionAnswer: (c)
Q.20
Two circular single turn coils are so arranged in two mutually perpendicular planes such that their centers coincide. The radius of each coil is 2cm and same current of 5A flows through them. The magnetic induction at the common centre is approximately
0%
a) 12 × 10-5 T
0%
b) 22 × 10-5 T
0%
c)32 ×10-5 T
0%
d)42 ×10-5 T
Explanation
Use following formulas to find magnetic field at centreHere B1 is perpendicular to B2 Answer:(b)
Q.21
A rectangular loop carrying a current i is situated near a long straight wire such that the wire is parallel to one of the sides of the loop and is in the plane of the loop. If a steady current I is established in the wire as shown in figure, the loop will
0%
a) rotate about an axis parallel to the wire
0%
b) move away from the wire
0%
c) move towards the wire
0%
d) have non zero force in the y direction
Explanation
Answer: (c)
Q.22
A wire of length l carries a current i along the x-axis. A magnetic field exists which is given aa B=Bo(i + j + k) T. The magnitude of the magnetic force acting on the wire is
0%
a)ilBo
0%
b) 3ilBo
0%
c)√2 ilBo
0%
d)√3 ilBo
Explanation
F=il × B F=i(li) × Bo(i + j + k)F=ilBo ( k - j| F |=√2 (ilBo)Answer: (c)
Q.23
In a cozaxial, straight cable , the central conductor and the outer conductor carry currents in opposite directions. The magnetic field is zero
0%
a) Outside the cable, if currents are equal
0%
b) inside the inner conductor, if currents are unequal
0%
c)inside the outer conductor
0%
d)inbetween the two conductors, if currents are equal or unequal
Explanation
Answer: (a)
Q.24
Two wires are placed at (2, 0, 0) and (-2, 0, 0) and are carrying equal currents along negative z-axis. Magnetic field at point (0, 2 ,0) is along
0%
a)positive x -axis
0%
b) negative x-axis
0%
c)positive y-axis
0%
d)negative z-axis
Explanation
Magnetic field produced by both the wire is in x-y plane Answer:(a)
Q.25
The vector form of Bio-savart law is
0%
a)
0%
b)
0%
c)
0%
d)
Explanation
Answer: (a)
Q.26
To obtain maximum intensity of magnetic field at appoint the angle between position vector of point and small elements of length of the conductor is
0%
a)0
0%
b) π/4
0%
c)π/2
0%
d)π
Explanation
Answer: (c)
Q.27
The value of magnetic field due to a small element of current carrying conductor at a distance r and lying on the plane perpendicular to the element of conductor is
0%
a) zero
0%
b) maximum
0%
c)inversely proportional to the current
0%
d)none of above
Explanation
Answer: (b)
Q.28
The value of intensity of magnetic field at a point due to a current carrying conductor is obtained from
0%
a) Gauss's law
0%
b) Faraday's law
0%
c)coulombs law
0%
d)Biot savart's law
Explanation
Answer:(d)
Q.29
The value of intensity of magnetic field at a point die to a current carrying conductor depends ..
0%
a) only on the value of current
0%
b) only on a small part of length of conductor
0%
c) on angle between the line joining the given point to the mid point of a small length and the distance between the small length of the point.
0%
d) On all above points
Explanation
Answer: (d)
Q.30
The resultant magnetic field at the point O due to the current carrying wire shown in figure is ...
0%
a) Points to wards right
0%
b) point towards left
0%
c)is zero
0%
d)is the same s due to the segment WX alone
Explanation
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
25
26
27
28
29
30
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