# Electricity and magnetism questions and answers pdf

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Tesla is a unit of a field strength b inductance c flux density d flux Ans: c. A permeable substance is one a which is a good conductor 6 which is a bad conductor c which is a strong magnet d through which the magnetic lines of force can pass very easily Ans: d. The materials having low retentivity are suitable for making a weak magnets b temporary magnets c permanent magnets d none of the above Ans: b.

A magnetic field exists around a iron b copper c aluminium d moving charges Ans: d. Ferrites are materials. The direction of magnetic lines of force is a from south pole to north pole b from north pole to south pole c from one end of the magnet to another d none of the above Ans: b. Which of the following is a vector quantity? The two conductors of a transmission line carry equal current I in opposite directions.

The force on each conductor is a proportional to 7 b proportional to X c proportional to distance between the conductors d inversely proportional to I Ans: b.

A material which is slightly repelled by a magnetic field is known as a ferromagnetic material b diamagnetic material c paramagnetic material d conducting material Ans: b. When an iron piece is placed in a magnetic field a the magnetic lines of force will bend away from their usual paths in order to go away from the piece b the magnetic lines of force will bend away from their usual paths in order to pass through the piece c the magnetic field will not be affected d the iron piece will break Ans: b.

The ratio of intensity of magnetisation to the magnetisation force is known as a flux density b susceptibility c relative permeability d none of the above Ans: b. Magnetising steel is normals difficult because a it corrodes easily 6 it has high permeability c it has high specific gravity d it has low permeability Ans: d. The left hand rule correlates to a current, induced e. A conductor of length L has current I passing through it, when it is placed parallel to a magnetic field.

The force between two long parallel conductors is inversely proportional to a radius of conductors b current in one conductor c product of current in two conductors d distance between the conductors Ans: d. Materials subjected to rapid reversal of magnetism should have a large area oiB-H loop b high permeability and low hysteresis loss c high co-ercivity and high retentivity d high co-ercivity and low density Ans: b.

Indicate which of the following material does not retain magnetism permanently. The main constituent of permalloy is a cobalt b chromium c nickel d tungsten Ans: c.

The use of permanent magnets is. Paramagnetic materials have relative permeability a slightly less than unity b equal to unity c slightly more than unity d equal to that ferromagnetic mate rials Ans: c. Degaussing is the process of a removal of magnetic impurities b removing gases from the materials c remagnetising metallic parts d demagnetising metallic parts Ans:.

Substances which have permeability less than the permeability of free space are known as a ferromagnetic b paramagnetic c diamagnetic d bipolar Ans: c. In the left hand rule, forefinger always represents a voltage b current c magnetic field d direction of force on the conductor Ans: c. Which of the following is a ferromagnetic material? Ferrites are a sub-group of a non-magnetic materials 6 ferro-magnetic materials c paramagnetic materials d ferri-magnetic materials Ans: d.

Gilbert is a unit of a electromotive force 6 magnetomotive force c conductance d permittivity Ans: b. The working of a meter is based on the use of a permanent magnet. In order to protect the meter functioning from stray magnetic fields a meter is surrounded by strong magnetic fields b a soft iron shielding is used c a plastic shielding is provided d a shielding of anon-magnetic material is used Ans: b.

Reciprocal of permeability is a reluctivity b susceptibility c permittivity d conductance Ans: a. The relative permeability is less than unity is case of a ferromagnetic materials b ferrites c non-ferrous materials d diamagnetic materials Ans: d. Which of the following is the unit of magnetic flux density? The magnetism left in the iron after exciting field has been removed is known as a permeance b residual magnetism c susceptance d reluctance Ans: b.

Which of the following is not a unit of flux? Which of the following is expected to have the maximum permeability? Out of the following statements, concerning an electric field, which statement is not true? When a magnet is in motion relative to a coil the induced e.

One maxwell is equal to a 10 webers b 10 webers c 10 webers d 10 webers Ans: d. When two ends of a circular uniform wire are joined to the terminals of a battery, the field at the center of the circle a will be zero b will be infinite c will depend on the amount of e. Susceptibility is positive for a non-magnetic substances b diamagnetic substances c ferromagnetic substances d none of the above Ans: c.

Two long parallel conductors carry A. If the conductors are separated by 20 mm, the force per meter of length of each conductor will be a N b 10 N c 1 N d 0. A mm long conductor is carrying a current of 10 A and is situated at right angles to a magnetic field having a flux density of 0.

A turn coil having an axial length of 30 mm and a radius of 10 mm is pivoted in a magnetic field having a flux density of 0. If the coil carries a current of 0. The electromagnet has 50 turns and a current of 1A flows through the coil.

If the length of the magnet circuit is mm, what is the magnetic field strength? What is the magnitude and the direction of force per 1. A square cross-sectional magnet has a pole strength of 1 x 10 Wb and cross sectional area of 20 mm x 20 mm. What is the strength at a distance of mm from the unit pole in air? The unit of flux is the same as that of a reluctance b resistance c permeance d pole strength Ans: d.

Unit for quantity of electricity is a ampere-hour b watt c joule d coulomb Ans: d. The most effective and quickest may of making a magnet from soft iron is by a placing it inside a coil carrying current b induction c the use of permanent magnet d rubbing with another magnet Ans: a.

The commonly used material for shielding or screening magnetism is a copper b aluminium c soft iron d brass Ans: c. If a copper disc is rotated rapidly below a freely suspended magnetic needle, the magnetic needle shall start rotating with a velocity a less than that of disc but in opposite direction b equal to that of disc and in the same direction c equal to that of disc and in the opposite direction d less than that of disc and in the same direction Ans: d.

A permanent magnet a attracts some substances and repels others b attracts all paramagnetic substances and repels others c attracts only ferromagnetic substances d attracts ferromagnetic substances and repels all others Ans: a. The retentivity a property of material is useful for the construction of a permanent magnets b transformers c non-magnetic substances d electromagnets Ans: a. The relative permeability of materials is not constant.

The materials are a bit inferior conductors of magnetic flux than air. Hysteresis loop in case of magnetically hard materials is more in shape as compared to magnetically soft materials. A keeper is used to a change the direction of magnetic lines b amplify flux c restore lost flux d provide a closed path for flux Ans: d. Magnetic moment is a a pole strength 6 universal constant c scalar quantity d vector quantity Ans: d. The change of cross-sectional area of conductor in magnetic field will affect a reluctance of conductor b resistance of conductor c a and b both in the same way d none of the above Ans: c.

The uniform magnetic field is a the field of a set of parallel conductors b the field of a single conductor c the field in which all lines of magnetic flux are parallel and equidistant d none of the above Ans: c. The magneto-motive force is a the voltage across the two ends of exciting coil b the flow of an electric current c the sum of all currents embraced by one line of magnetic field d the passage of magnetic field through an exciting coil Ans: c.

What will be the current passing through the ring shaped air cored coil when number of turns is and ampere turns are ? Which of the following statements is correct? A certain amount of current flows through a ring-shaped coil with fixed number of turns. How does the magnetic induction B varies inside the coil if an iron core is threaded into coil without dimensional change of coil? The magnetic reluctance of a material a decreases with increasing cross sectional area of material 6 increases with increasing cross-sec-tional area of material c does not vary with increasing cross-sectional area of material d any of the above Ans: a.

The initial permeability of an iron rod is a the highest permeability of the iron rod b the lowest permeability of the iron rod c the permeability at the end of the iron rod d the permeability almost in non-magnetised state Ans: d. How does the magnetic compass needle behave in a magnetic field? In a simple magnetic field the strength of magnet flux a is constant and has same value in energy part of the magnetic field 6 increases continuously from initial value to final value c decreases continuously from initial value to final value d first increases and then decreases till it becomes zero Ans: d.

The stray line of magnetic flux is defined as a a line vertical to the flux lines b the mean length of a ring shaped coil c a line of magnetic flux in a non-uniform field d a line of magnetic flux which does not follow the designed path Ans: d.

The bar magnet has a the dipole moment b monopole moment c a and b both d none of the above Ans: a. Which of the following materials are diamagnetic? Which of the following type of materials are not very important for engineering applications?

For which of the following materials the saturation value is the highest? The magnetic materials exhibit the property of magnetisation because of a orbital motion of electrons b spin of electrons c spin of nucleus d either of these e all of the above Ans: c. For which of the following materials the net magnetic moment should be zero? The attraction capacity of electromagnet will increase if the a core length increases i b core area increases c flux density decreases d flux density increases Ans: d.

Temporary magnets are used in a loud-speakers b generators c motors d all of the above Ans: d. Main causes of noisy solenoid are a strong tendency of fan out of laminations at the end caused by repulsion among magnetic lines of force b uneven bearing surface, caused by dirt or uneven wear between moving and stationary parts c both of above d none of the above Ans: c.

Strength of an electromagnet can be increased by a increasing the cross-sectional area b increasing the number of turns c increasing current supply d all above methods Ans:. Core of an electromagnet should have a low coercivity 6 high susceptibility c both of the above d none of the above Ans: c. Magnetism of a magnet can be destroyed by a heating b hammering c by inductive action of another magnet d by all above methods Ans: d.

Your email address will not be published. Tesla is a unit of a field strength b inductance c flux density d flux Ans: c 2. A permeable substance is one a which is a good conductor 6 which is a bad conductor c which is a strong magnet d through which the magnetic lines of force can pass very easily Ans: d 3.

The materials having low retentivity are suitable for making a weak magnets b temporary magnets c permanent magnets d none of the above Ans: b 4. A magnetic field exists around a iron b copper c aluminium d moving charges Ans: d 5.

The direction of magnetic lines of force is a from south pole to north pole b from north pole to south pole c from one end of the magnet to another d none of the above Ans: b 8.

The force on each conductor is a proportional to 7 b proportional to X c proportional to distance between the conductors d inversely proportional to I Ans: b A material which is slightly repelled by a magnetic field is known as a ferromagnetic material b diamagnetic material c paramagnetic material d conducting material Ans: b When an iron piece is placed in a magnetic field a the magnetic lines of force will bend away from their usual paths in order to go away from the piece b the magnetic lines of force will bend away from their usual paths in order to pass through the piece c the magnetic field will not be affected d the iron piece will break Ans: b The ratio of intensity of magnetisation to the magnetisation force is known as a flux density b susceptibility c relative permeability d none of the above Ans: b Magnetising steel is normals difficult because a it corrodes easily 6 it has high permeability c it has high specific gravity d it has low permeability Ans: d The force between two long parallel conductors is inversely proportional to a radius of conductors b current in one conductor c product of current in two conductors d distance between the conductors Ans: d Materials subjected to rapid reversal of magnetism should have a large area oiB-H loop b high permeability and low hysteresis loss c high co-ercivity and high retentivity d high co-ercivity and low density Ans: b ## electromagnetism multiple choice questions with answers pdf

A electric circuit B electric resistance C magnetic domain D electric field 4 When a portable radio is playing, the current in the radio is 0. If the resistance of the radio is A electric current B insulator C conductor D electromagnet 7 What is the unit of charge? A Coulomb B Newton. C Watt 8 Which of the following does not describe the magnetic force between two magnets? A The like poles attract.

The electromagnet has 50 turns and a current of 1A flows through the coil. Ans: c, Ans: b, What are two ways that magnetism is produced? Ans: d, Answers Answer 1 Magnetism is caused by electric charges in motion. ## magnetism questions and answers pdf

Tesla is a unit of a field strength b inductance c flux density d flux Ans: c. A permeable substance is one a which is a good conductor 6 which is a bad conductor c which is a strong magnet d through which the magnetic lines of force can pass very easily Ans: d. The materials having low retentivity are suitable for making a weak magnets b temporary magnets c permanent magnets d none of the above Ans: b. A magnetic field exists around a iron b copper c aluminium d moving charges Ans: d.

These solutions for Current Electricity And Magnetism are extremely popular among Class 8 students for Science Current Electricity And Magnetism Solutions come handy for quickly completing your homework and preparing for exams. Write proper words from the following group of words in the blanks. Three electric cells of potential difference 1.