Class 10- Physics Magnetic Effects of Electric CurrentContact Number: 9667591930 / 8527521718Class 10- Physics Magnetic Effects of Electric CurrentContact Number: 9667591930 / 8527521718The direction of magnetic field around a straight conductor carrying can be determined by
1. Fleming's left hand rule
2. Lenz's law
3. Right hand thumb rule
4. Flemin's right hand rule
Magnetic field is produced by the flow of current in a staright wire. This phenomenon was discovered by
1. Coulomb
2. Oersted
3. Faraday
4. Maxwell
The magnetic field produced due to a circular wire at its centre is
1. at to the plane of the wire
2. at to the plane of the wire
3. in the plane of the wire
4. perpendicular to the plane of the wire
A magnetic field exerts no force on
1. a stationary electric charge
2. a magnet
3. an electric charge moving perpendicular to its direction
4. an unmagnetised
At the centre of a magnet, the magnetism is
1. zero
2. same as the pole
3. maximum
4. minimum
Which of the following instruments works by electromagnetic induction?
1. dynamo
2. moving coil galvanometer
3. telephone receiver
4. simple motor
A DC generator is based on the principal of
1. magnetic effect of current
2. heating effect of current
3. energy dessipation
4. electromagnetic induction
The use of fuses in electric power line is
1. just to show an indication where there is an over load
2. as a switch to use in an emergency
3. to keep main vaoltage constant
4. to open the lines permanently when there is an overload
When the main switch of the house circuit is put off, it disconnects the
1. earth wire
2. live and neutral wires
3. live wire
4. neutral wire
For making a strong electromagnet, the material of the core should be
1. brass
2. laminated steel strips
3. soft iron
4. steel
A soft iron bar is introduced inside a current carrying solenoid. The magnetic field inside the solenoid
1. will increase
2. will remain unaffected
3. will become zero
4. will decrease
The magnetic field lines inside a current carrying solenoid are
1. circular and they do not intersect each other
2. circular at the ends but they are parallel to the axis inside the sloenoid
3. along the axis and parallel to each other
4. perpendicular to the axis and eqiudistant from each other
Which of the following describes the common domestic power supplied in India?
1. 220 V, 100 Hz
2. 110 V, 100 Hz
3. 220 V, 50 Hz
4. 110 V, 50 Hz
Potential difference between a live wire and the neutral wire is
1. 200 V
2. 220 V
3. 150 V
4. 210 V
A device for producing electric current is called
1. generator
2. voltmeter
3. galvanometer
4. ammeter
An electric motor converts
1. electrical energy into heat energy
2. electrical energy into mechanical enrgy
3. mechanical energy into electrial energy
4. mechanical energy iinto heat energy
An electrical generator converts
1. electrical enrgy into chemical energy
2. mehanical energy into electrical energy
3. electrical energy into mechanical energy
4. mechanical energy into heat energy
The ring system of wiring is better than the tree system because
1. it is less expensive
2. all appliances can be joined in series
3. less power is consumed in the ring system
4. it can work even at low voltage supply
Four students plotted the sketch of the patterens of magnetic field lines representing the magnetic field around a current carrying straight wire as shown in figures A, B, C and D. Which of the sketches is correct?
1. A
2. B
3. C
4. D
A soft iron bar is enclosed by a coil of insulated copper wire as shown in figure. When the plug of the key is closed, the face B of the iron bar marked as
1. N-pole
2. S-pole
3. N-pole if current is large
4. S-pole if current is small
Magnetic field lines determine
1. the space of the magnetic field
2. only the direction of the magnetic field
3. only the relative strength of the magnetic field
4. both the direction and the relative strength of the magnetic field
The magnetic field near a long straight wire is described by
1. straight field lines parallel to the wire
2. straight field lines perpendicular to the wire
3. concentric circles centred on the wire
4. radial field lines starting from the wire
Commercial electric motors do not use
1. an electromagnet to rotate the armature
2. a permanent magnet to rotate the armature
3. a soft iron core on which the coil is wound
4. effectively large number of turns of conducting wires in the current-carrying coil
At the time of short circuit,the current in the circuit
1. vary continously
2. reduces considerably
3. increases heavily
4. does not change
Who invented electric generator
1. Oersted
2. Coulomb
3. Rutherford
4. Michael Faraday
a magnetic field
1. always exerts a force on a charged particle
2. never exerts a force on a charged particle
3. exerts a force, if the charged particle is moving across the magnetic field lines
4. exerts a force, if the charged particle is moving along the magnetic field lines
If a copper rod carrioes a direct current, the mahnetic field associated with the current will be
1. only inside the rod
2. only outside the rod
3. both inside and outside the rod
4. neither inside nor outside the rod
An electric charge in uniform motion produces
1. an electric field only
2. a magnetic field only
3. both electric and magnetic fields
4. no such field at all
In a safety fuse, the temperature to which the wire gets heated does not depend upon
1. the radius of the wire
2. the type of alloy used
3. the magnitude of the current
4. none of these
An electron is travelling horizontally towards east. A magnetic field in vertically downward direction exerts a force on the electron along
1. east
2. west
3. north
4. south
Induced current flows through a coil
1. more than the period duriing which flux changes through it
2. lass than the period during which flux changes through it
3. only for the period during which flux changes through it
4. none of the above
When a fuse is rated at 8A, it means
1. it will work only if current is 8 A
2. it will burn if current exceeds 8 A
3. it will not work if current is less than 8 A
4. it has a resistance of 8 ohm
Power is transmitted from a power-house on high voltage AC as
1. power cannot be generated at low voltages
2. a precaution against theft of transmission lines.
3. the rate of transmission is faster at high voltage
4. it is more economical due to the less power wasted
A circular loop is suspended in air as shown in figure. When the loop is seen from above, current flows anticlockwise and when seen from below, current flows clockwise. This loop behaves as a magnet. The N-pole of this magnet is one
1. the upper face
2. lower face
3. the lower face if current is large
4. upper face if current is large
A student connects a coil of wire with a sensitive galvanometer as shown in figure. He will observe the deflection in the galvanometer if bar magnet is
1. placed near one of the faces of the coil and parallel to the axis of the coil.
2. placed near one of the faces of the coil and perpendicular to the axis of the coil
3. placed inside the coil
4. moves towards or away from the coil parallel to the axis of the coil
Electric supply of a house is through a 15 A fuse. When a 2000 W heater is used in this house, how many 100 W bulbs can be used simultaneously? The supply is at 220 V, and the heater and the bulbs are rated for 220 V.
1. 12
2. 13
3. 14
4. 15
A current flows in a conductor from east to west. The direction of the magnetic field at a point above the conductor is
1. towards north
2. towards south
3. towards east
4. towards west
A compass needle placed just above a wire in which electrons are towards west, will point
1. east
2. north
3. west
4. south
A positively charged particle moving due east enters a region of uniform magnetic field directed vertically upwards. The particle will
1. get deflected in vertically upward direction
2. move in circular path with an increased speed
3. move in circular path with a decreased speed
4. move in circular path with a uniform speed
When a magnetic compass needle is carried nearby to a straight wire carrying current, then
I. the straight wire causes a noticeable deflection in the compass needle
II. the aligment of the needle is tangential to an imaginary circle with straight wire as its centre and has a plane perpendicular to the wire
1. (I) is correct
2. (II) is correct
3. both (I) and (II) are correct
4. neither (I) nor (II) is correct
If an electron is moving with velocity produces a magnetic field , then
1. the direction of field will be same as the direction of velocity
2. the direction of field will be opposite to the direction of velocity
3. the direction of field will be perpendicular to the direction of velocity
4. the direction of field does not depend upon the direction of velocity
Which of the following is correct regarding the nature of parallel and anti-parallel currents?
1. Parallel currents repel an dantiparallel currents attract.
2. Parallel currents attracts and antiparallel currents repel.
3. No force exist due to both currents.
4. None of these
The magnetism of a magnet due to
1. the earth
2. cosmic rays
3. the spin motion of electrons
4. pressure of big magnet inside the earth
The magnetic field lines due to a bar magnet are correctly shown in figure
A charged particle is moving along a magnetic field line. The magnetic force on the particle is
1. along its velocity
2. opposite to its velocity
3. perpendicular to its velocity
4. zero
Choose the incorrect statement from the following regarding magnetic lines of field:
1. the direction of magnetic field at a point is taken to be the directionin which the north pole of a magnetic compass needle points.
2. Magnetic field lines are closed curves
3. If magnetic field lines are parallel and equidistant, they represent zero field strength.
4. Relative strength of magnetic field is shown by the degree of closeness of the field lines.
If the key in the arrangements, in the given figure is taken out (the circuit is made open) and magnetic field lines are drwn over the horizontal plane ABCD, the lines are:
1. concentric circles
2. elliptial in shape
3. straight lines parallel to each other
4. concentric circles near the point O but of elliptical shapes as we go away from it.
A circular loop placed perpendicular to the plane of paper carries a current when the key is ON. The current as seen fro points A and B (in the plane of paper and on the axis of the coil) is aniclockwise and clockwise respectively. The magnetic field lines point from B to A. The N-pole of the resulstant magnet is on the face close to:
1. A
2. B
3. A if the current is small, and B if the current is large
4. B if the current is small, and A if the current is large
For a current in a long straight solenoid, N and S-pole are created at the two ends. Amoong the following statements, the incorrect statement is:
1. the field lines inside the solenoid are in the form of straight lines which indicate that the magnetic field is the same at all points inside the solenoid
2. 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
3. the pattern of the magnetic field associated with the solenoid is different from the patteren of the mahnetic field around a bar magnet
4. the N- and S-poles exchange positions when the direction of current through the solenoid is reversed
A uniform magnetic field exists in the plane of paper point from left to right as shown in figure. In th field, an electron and a proton move a shown. The electron and the proton experience forces.
1. both pointin into the plane of paper
2. both pointing out of the plane of paper
3. pointing into the plane of paper and out of the plane of paper, respectively
4. pointing opposite and along the direction of the uniform magnetic field respectively
