CBSE X Science Magnetic Effects of Current - EducareHut (Next Gen Knowledge Point)

Results

#1. If two circular coils can be arranged in any of the three situations as shown in the diagrams below, then their mutual induction will be:

Maximum in situation a

Maximum in situation b

Maximum in situation c

The same in all situations

#2. A soft iron bar is introduced inside the current carrying solenoid. The magnetic field inside the solenoid

will decrease

will remains same

will increase

will become zero

Explanation: (c) Soft iron inside the current carrying solenoid act as an electromagnet.

#3. Which among of these are the main characteristics of fuse element?

High conductivity

low melting point

do not burn due to oxidation

All of the other answer

Explanation: Fuse wire must have all the characteristic to prevent from a possible damage.

#4. A uniform magnetic field exists in the plane of paper pointing from left to right as shown in figure. In the field an electron and a proton move as shown. The electron and the proton experience.

Forces both pointing into the plane of paper

Forces both pointing out of the plane of paper

Forces pointing into the plane of paper and out of the plane of paper, respectively

Force pointing opposite and along the direction of the uniform magnetic field respectively

Explanation: Direction of current is taken as opposite to the flow of electron or in the direction of flow of protons.

In the given figure, the proton and electron are moving in opposite direction to each other and in perpendicular to the direction of magnetic field. So, current due to both electron and proton are in same direction. Hence, the forces acting on both will be in the same direction. By Fleming’s left hand rule the direction, force is pointing into the plane of paper.

#5. A magnetic field directed in north direction acts on an electron moving in east direction. The magnetic force on the electron will act

vertically upwards.

towards east.

vertically downwards.

towards north.

#6. A.C generator works on the principle of

force experience by a conductor in magnetic field

electromagnetic induction

electrostatic

force experience by a charge particle in electric field.

Explanation: Generator works on principle of electromagnetic induction.

#7. A positive charge is moving upwards in a magnetic field directed towards north. The particle will be deflected towards

west

north

south

east

Explanation: (a) Apply fleming’s left hand rule

#8. The main advantage of A.C power transmission over D.C power transmission over’ long distance is

AC transmit without much loss of energy

less insulation problem

less problem of instability

easy transformation.

Explanation: AC transmit over a long distance without much loss of energy as compare to DC.

#9. Magnetic lines of force inside current carrying solenoid are

perpendicular to axis.

along the axis and are parallel to each other.

parallel inside the solenoid and circular at the ends.

circular.

#10. Which of the following statement is not correct about the magnetic field?

Magnetic field lines form a continuous closed curve.

Magnetic field line do not interest each other.

Direction of tangent at any point on the magnetic field line curve gives the direction of magnetic field at that point.

Outside the magnet, magnetic field lines go from South to North pole of the magnet.

Explanation:
(d) Outside the magnet, magnetic field line emerges from North-pole and moves towards south-pole.

#11. The phenomenon of electromagnetic induction is

The process of charging a body.

The process of generating magnetic field due to a current passing through a coil.

Producing induced current in a coil due to relative motion between a magnet and the coil.

The process of rotating a coil of an electric motor.

#12. Earth wire carries

current

voltage

no current

heat

Explanation: Earth wire carries no current.

#13. The factors on which one magnetic field strength produced by current carrying solenoids depends are

Magnitude of current

Number of turns

Nature of core material

All of the other 3 answers

Explanation: (d) Factors shown in (a), (b) and (c).

#14. A magnet is moved towards a coil (i) quickly (ii) slowly. The induced potential difference

#15. A coil of insulated copper wire is connected to a galvanometer forming a loop and a magnet id. A: Held stationary B: Moved away along its axis C: Moved towards along its axis.There will be a induced current in:

A only

A and B only

B and C only

A, B and C

#16. For a current in a long straight solenoid N-pole and S-pole are created at the two ends. Among the following statements, the incorrect statement is

The field lines inside the solenoid are in the form of straight lines which indicates that the magnetic field is the same at all points inside the solenoid.

The strong magnetic field produced inside the solenoid can be used to magnetise a piece of magnetic material like soft iron, when placed inside the coil.

The pattern of the magnetic field associated with the solenoid is different from the pattern of the magnetic field around a bar magnet.

The N-pole and S-pole exchange position when the direction of current through the solenoid is reversed.

Explanation: A solenoid behaves like a bar magnet. Hence the pattern of magnetic field associated with solenoid and around the bar magnet is same.

#17. The strength of magnetic field inside a long current carrying straight solenoid is

More at the ends than at the centre

Minimum in the middle

Same at all points

Found to increase from one end to the other

Explanation: Inside the solenoid, magnetic field lines are parallel to each other hence forming a uniform field strength which indicates that the magnetic field is the same at all points inside the solenoid.

#18. The north pole of Earth’s magnet is in the:

Geographical South

Geographical East

Geographical West

Geographical North

#19. The essential difference between an AC generator and a DC generator is that

AC generator has an electromagnet while a DC generator has permanent magnet.

DC generator will generate a higher voltage.

AC generator will generate a higher voltage.

AC generator has slip rings while the DC generator has a commutator.

#20. A current through a horizontal power line flows from south to North direction. The direction of magnetic field line 0.5m above it is

North

South

West

East

Explanation:(a) Apply right-hand thumb rule.

#21. A soft iron bar is inserted inside a current-carrying solenoid. The magnetic field inside the solenoid:

Will decrease

Will increase

Will become zero

Will remain the same

#22. A D.C generator works on the principle of

ohm's law

Joule’s law of heating

faraday’s law of electromagnetic induction.

none of the above

Explanation: electric generator works on the basis of electromagnetic induction.

#23. The most important safety method used for protecting home appliances from short circuiting or overloading is

earthing

use of fuse

use of stabilizers

use of electric meter

Explanation: It is most important method for protecting the electrical devices from short circuiting or overloading by stopping the flow of any large electric current exceeds from its rating.

#24. What should be the core of an electromagnet?

soft iron

hard iron

rusted iron

none of answer

#25. Choose the incorrect statement.

Fleming's right hand rule is a simple rule to know the direction of induced current.

The right hand thumb rule is used to find the direction of magnetic fields due to current carrying conductors.

The difference between the direct and alternating currents is that the direct current always flows in one direction, where as the alternating current reverses its direction periodically.

In India, the AC changes direction after every1/50 second.

Explanation: Here option (a), (b) and (c) are knowledge based options and are correct.

Option (d) is incorrect because the frequency of ‘AC’ in India is 50 cycle/s. So, time period of AC is 1/50 s. We know that, AC changes its direction after every half time period, i.e., 1/ (2 × 50) or1/100 s. So, in India the AC changes direction after every 1/100 s.

Finish