NTSE SAT Physics - Magnetic Effects of Electric Current
Exam Duration: 45 Mins Total Questions : 30
The direction of magnetic field at the centre of a coil carrying in clockwise direction
- (a)
along the axis of the coil inwards
- (b)
along the axis of the coil outwards
- (c)
perpendicular to the axis
- (d)
none of these
The phenomenon of electromagnetic induction was discovered by
- (a)
Maxwell
- (b)
Fleming
- (c)
Faraday
- (d)
Lenz
1 T equals
- (a)
1 NA-1m-1
- (b)
1 NAM2
- (c)
1 NA-1m-2
- (d)
1 N-1 Am
The wire with green plastic covering is
- (a)
live wire
- (b)
earth wire
- (c)
neutral wire
- (d)
none of these
Magnetic field produced at the centre of a current carrying circular wire is
- (a)
Directly proportional to the square of the radius of the circular wire
- (b)
Directly proportional to the radius of the circular wire
- (c)
Inversely proportional to the square of the radius of the circular wire
- (d)
Inversely proportional to the radius of the circular wire
The magnetic field lines inside a long, current carrying solenoid are nearly:
- (a)
Straight
- (b)
Circular
- (c)
Parabolic
- (d)
Elliptical
The direction of the force on a current-carrying wire placed in a magnetic field depends on:
- (a)
The direction of the current
- (b)
The direction of the field
- (c)
The direction of current as well as field
- (d)
Neither the direction of current nor the direction of field
Electromagnetic induction is the
- (a)
Charging of a body with a positive charge
- (b)
Production of current by relative motion between a magnet and a coil
- (c)
Rotation of the coil of an electric motor
- (d)
Generation of magnetic field due to a current carrying solenoid
When current is circular, the associated magnetic field is
- (a)
Straight
- (b)
Elliptical
- (c)
Circular
- (d)
Parabolic.
The electric device which works on the phenomenon of force on a current carrying conductor in a magnetic field is
- (a)
Generator
- (b)
Accelerator
- (c)
Motor
- (d)
Transformer.
In domestic electric circuits, fuse must be placed in series with
- (a)
Earth wire
- (b)
Neutral wire
- (c)
Live wire
- (d)
Any of the three wires
Which of the following correctly describes the magnetic field near a long straight wire?
- (a)
The field consists of straight lines perpendicular to the wire
- (b)
The field consists of straight lines parallel to the wire.
- (c)
The field consists of radial lines originating from the wire.
- (d)
The field consists of concentric circles centred on the wire.
Which of the following instruments works by electromagnetic induction?
- (a)
telephone receiver
- (b)
simple motor
- (c)
dynamo
- (d)
moving coil galvanometer.
Potential difference between a live wire and the neutral wire is
- (a)
200 volt
- (b)
150 volt
- (c)
210 volt
- (d)
220 volt
The most important safety device method used for protecting electrical appliances from short circuiting or overloading is:
- (a)
Earthing
- (b)
Use of stabilizers
- (c)
Use of electric meter
- (d)
Use of fuse
Current flowing in conductors A and B is same, what is the ratio of the magnetic field produced around the conductor A at a distance of 5 cm from the conductor to the magnetic field produced around the conductor B at a distance of 2 cm from this conductor is
- (a)
0.04
- (b)
0.4
- (c)
4.0
- (d)
10
A positively charged particle say an alpha particle projected towards west is deflected towards north by a magnetic field. The direction of the magnetic field is:
- (a)
Upward
- (b)
Downward
- (c)
Towards south
- (d)
Towards east
Two parallel conductor carrying current in the same directions
- (a)
Repel each other
- (b)
Attract each other
- (c)
Sometimes attract and sometimes repel each other
- (d)
None of these
If the plug of the key is taken out (i.e. the circuit is made open) and magnetic field lines are drawn over the horizontal plane white sheet of paper, the lines are:
- (a)
Concentric circles
- (b)
Elliptical in shape
- (c)
Straight lines parallel to. each other
- (d)
Parabolic in shape
In these type of Questions, two statements are given. Choose the correct option by following directions given below:
(a) Statement I is correct and Statement II is correct explanation of the statement I.
(b) Statement I is correct but Statement II is not the correct explanation of the statement I.
(c) Statement I is true but statement II is not true.
(d) Statement I is not true but statement II is true.
Statement I: A soft iron bar placed inside a solenoid carrying current is magnetised.
Statement II: Magnetic field. inside a long solenoid carrying current is non-uniform.
- (a)
A
- (b)
B
- (c)
C
- (d)
D
Current can be made to flow through a coil without connecting the coil with a battery. Which of the following procedures would be most suited to test this fact?
- (a)
Connect a galvanometer across the ends of the coil and observe if galvanometer shows a
deflection, when a bar magnet is placed near the one end of the coil. - (b)
Connect a galvanometer across the ends of the coil and observe if galvanometer shows a deflection, when a bar magnet is placed inside the coil.
- (c)
Connect the galvanometer across the ends of the coil and observe if galvanometer shows a deflection, when a bar magnet is moved towards or away from the coil and along the axis of the coil.
- (d)
Connect the galvanometer across the ends of the coil and observe if galvanometer shows a deflection, when a bar magnet is moved at right to the axis of the coil
The magnetic field at a point due to a current carrying conductor is directly proportional to
- (a)
Resistance of the conductor
- (b)
Thickness of the conductor
- (c)
Current flowing through the conductor
- (d)
(a) and (b) both
Two long parallel wires are at a distance of 1m.If both of them carry 1 A of current, them the force of attraction per unit length between the two wires is
- (a)
2 x 10-7 N m-1
- (b)
2 x 10-8 N m-1
- (c)
5 x 10-8 N m-1
- (d)
5 x 10-7 N m-1
A conductor of length I is moved perpendicular to uniform magnetic field B with velocity V as shown in figure.
- (a)
zero
- (b)
BIV
- (c)
BIV/2
- (d)
BI2V/2
An induction furnace works on the principle of
- (a)
Self induction
- (b)
Mutual induction
- (c)
Eddy currents
- (d)
Faraday's laws
The mutual inductance between two coils depends o
- (a)
Medium between the coils only
- (b)
Separation between two coils only
- (c)
Both a and (b)
- (d)
None of (a) and (b)
An electron moves along the time which lies in the same plane a circular loop of conducting wires. What will be the direction of the current induced in the loop if any?
- (a)
No current will be induced
- (b)
The current will be clockwise
- (c)
The current will be anticlockwise
- (d)
The current will change direction as the electron passes by.
A solenoid with 1000 turns per unit length has a fluse density of 2.52 x 10-3T at its centre. The current in the solenoid is
- (a)
2A
- (b)
1A
- (c)
3A
- (d)
4A
Theradius of curvature of the paths of a chargedparticle in Uniform magnetic fieldis directly proportional to the
- (a)
Intensity of field
- (b)
Charge on the particle
- (c)
Work on the particle
- (d)
Momentum of the particle
Two parallel wires carrying currents of 3Ain opposite directions are separated by a small distance. They will
- (a)
Attract each other
- (b)
Repel each other
- (c)
Not affect each other
- (d)
Oscillat
