Physics : Electricity

 PHYSICS – 3

MAGNETISM : 

1) Give examples for magnetic substances?

Ans : Iron, Nickel, Cobalt

2) Give examples for non-magnetic substances?

Ans : Brass, Paper, Wood

3) The property of a magnetism exhibited by magnetic substances has given into the ____ of electron in atoms

Ans : configuration

4) The idea of magnetism was first proposed by ________

Ans : Weber

5) Magnet attracts the iron due to _______

Ans : Induction

6) Magnetic poles always exist in_______

Ans : pairs

7) Two poles of a bar magnet have equal _______

Ans : strength

8) A magnet can be demagnetized by ___________

Ans : tapping o r hammering or heating

9) In soft iron the ailments are distributed easily. Therefore it is used to make _____

Ans : electromagnets

10) _______ is the unit of magnetic pole strength in M.K.S.system

Ans : Weber

11) The unit of an intensity of a magnetic field in C.G.S. system is ______

Ans: Gauss

12)  One Tesla is ________

Ans : 104 Gauss

13) When the North Pole of the bar magnet facing North Pole of the earth, the null points are formed on _______

Ans : equatorial line

14) Whe the south pole of the bar magnet facing North Pole on the earth, the null points are formed on ______

Ans : axial line

15) The line joining the two poles is ________

Ans : magnetic axis

Magnetic  Properties of Materials : 

16) All materials can be classified in to ____________ magnetic materials.

Ans : 1) dia 2) para and 3) ferro

17) Oxygen, solution of salts of nickel, manganese, aluminium, platinum and chromium are some of the ______ substances.

Ans : paramagnetic

18) Iron, Cobalt, Nickel, Gadolinium, Dysprosium, and large number of their alloys are _______ substances.

Ans: ferromagnetic

19) The property of retaining certain amount of intensity of magnetization even after removal of applied magnetic field is called ________

Ans : retentivity

20) ____________ substances are those in which the resultant magnetic moment of individual atoms is zero.

Ans : dia-magnetic 

21) Manganese is an example for ____ magnetic material.

Ans : para 

22) In each atom _____ revolve round the nucleus in orbits.

Ans : electrons

23) Electron carries _______ charge

Ans : negative

24) The motion of the electrons cause _____ and electric currents to appear in orbit.

Ans : current

25) The electric current produces a _______ field

Ans : magnetic

26) The magnetic field in the atom or molecule behaves as a ________

Ans : magnet

27) The magnet is said to have _______

Ans : magnetic moment

28) The spin motion of an electron also gives rise to a ________

Ans : magnetic behavior

29) When a substance is placed in a magnetic field, the atomic magnets tend to align _____ to the direction of the applied field.

Ans : parallel

30) The cause for magnetism in a steel magnet is due to the ________

Ans : spi of electrons

31) Iron is ferromagnetic below_______

Ans : 770 ° C

32) An electromagnet  is made of _________

Ans : soft iron

33) Permanent magnets are made of _______

Ans : steel

34) The magnetism of the atom is due to _____ around nucleus and spin of the electron.

Ans : electrons

35) The ferromagnetic substances are strongly attracted by a _________

Ans : magnet

36) When paramagnetic substance is brought near a magnetic pole of a bar magnet, it develops an opposite or unlike ______ and therefore it is attracted by it.

Ans : pole

37) A paramagnetic substance suspended freely in a magnetic field is attracted towards stronger field and tends align along the direction of the ________

Ans : magnetic field

38) The S.I.Unit of magnetic induction is ________

Ans : Tesla

39) Example of a para magnetic  substance is ______

Ans : Oxygen

40) The S.I.Unit of magnetic flux density is _________

Ans : Newton/ampere – metre

41) The magnetic nature of a substance is determined by ________

Ans : Spin of its electrons

42) One Tesla is equivalent to _________

Ans : 10 4 gauss

43) The S.I.unit of magnetic flux  is _________

Ans : Weber

44) The magnetism of a magnet may be destroyed by ___________

Ans : tapping, heating, hammering

45) Spontaneous magnetization exists only in __________

Ans: Ferromagnetic substances

46)  The exact test for magnetism is _________

Ans : Repulsion

47) Substances very strongly attracted by the magnet , called__________

Ans : Ferromagnets

48) _____ is not a diamagnetic substance

Ans: Iron

49) Air, water, bismuth, gold, alcohol, mercury and hydrogen are some of the _____ substances.

Ans : diamagnetic

50) The S.I.Unit of magnetic moment is _________

Ans : Ampere – meter 2

ELECTRICITY

Simple Electric Circuits:

1) The Unit of electric current is ______

Ans : Amperes

2) Potential difference is measured in _______

Ans : Volts

3) The instrument used for measuring current is _______

Ans : Ammeter

4) Tap-Key is used to make and _______ an electric circuit.

Ans : break

5) The study of electric charges at rest is called ________

Ans: static electricity

6) The study of various effects of electrical charges in motion  is called _______

Ans : Current electricity

7)  The flow of chargers in a conductor constitutes an ______ in it.

Ans : electric current

8) The current is measured in amperes using an ______

Ans : Ammeter

9) Free electrons are available in_________

Ans : metals

10) Unit of power is ________

Ans : Watt or Joule/Sec

11) When negative terminal of a cell is connected to the positive terminal of the next cell, then the cells are said to be in _____________

Ans : Series

12) When all positive terminals of two or more cells are connected to a single point and similarly all the negative terminals are connected to another single point, then the cells are said to be connected in _________

Ans : Parallel

13) The P.D. of an electrical device or energy source is called its _________

Ans : Voltage

14) Battery or cell is the seat of _______

Ans : e.m.f. 

15) E.m.f. is nothing but work done per unit ______ chanrge.

Ans : positive

16) E.M.f. is measured in _______

Ans : Volts

Electrical Resistance: 

1) The electrical property of a conductor which opposites the flow of electrons through it is called ________

Ans : Electric resistance

2) _______ are good conductors of electricity

Ans : metals

3) The unit of resistance is _______

Ans : Ohm

4) Metals are good ________

Ans : conductors

5) Metallic nature is due to availability of ________ electrons

Ans : free

6) Metals are good conductors because of free ______

Ans : electrons

7) Resistance opposes the flow of _________

Ans: electrons

8) In a conductor, the flow of current is flow of free ______

Ans : electrons

9) The instrument to measure current is ________

Ans : Ammeter

LAW OF RESISTANCE: 

1) The resistance of some semiconductors like ______ changes significantly when exposed to light.

Ans : selenium

2) Addition of _________ changes the resistance of  a material.

Ans : impurities

3) Impurities have a marked effect on the resistance of _________

Ans : Semiconductors

HEATING EFFECTS OF ELECTRIC CURRENT: 

1) When electric current passes through a resistance, _____ is produced.

Ans : heat

2) _________ of an electrical appliance is defined as the rate at which electrical energy is consumed by it.

Ans : Wattage

3) The units of household consumption of electrical energy are ______

Ans : Kilowatt hour

3) One kilowatt hour =

Ans :  36 x 10 5 watt second

4) According  to Joule’s law the amount of work done is directly proportional to ________

Ans : heat produced

5) One Kilo Watt Hour (KWH) =

Ans : 1000 Watt Hours

6) One Watt Hour =

Ans: 3600 Watt – Second

7) Electric Power (P) = Voltage x ________

Ans : current

8) The S.I. unit of electrical energy is _________

Ans : Joule

9) _______________ of an electrical appliance is defined as the rate at which electrical energy is consumed.

Ans : Wattage

10) A heater is marked 1000 W.  The energy it consumes in an hour is _________

Ans : One KWH

11) The unit of household consumption of electrical energy is _______

Ans : KWH

12) A bulb of 40 watt is connected with 220 volts. The current flowing through it ______

Ans : 0.18 amp

13) A 200 W heater is used 6 hours daily and the cost of one unit of electricity is 60 paise.  The cost of the energy consumed in the month of June is ________

Ans: Rs.216/-

14) If a unit of electricity costs 80 paise, the cost of consumption using ten lamps of each 60 watt in a month of 30 days is __________

Ans : 90 KHW  or Units

FARADAY’S LAWS OF ELECTROLYSIS : 

1) Electro plating is a process of ________________ of costlier or less corrodible metals on a base metal.

Ans: coating a thin film

2) _____________ is a method of obtaining exact copy of an engraved block containing letters or figures by the methods of electrolysis.

Ans : Electro-typing

3) The vessel which contains an electrolyte and allows electrolysis to take place is called a ________

Ans : Voltameter or Electrolytic Cell

4) For refining and extracting metals ______ is used.

Ans: electrolysis

MAGNETIC EFFECTS OF ELECTRIC CURRENT : 

1) The direction of force (F) on the conductor in Fleming’s Left Hand Rule is represented in ______

Ans : Thumb

2) _______ Ammeter is used to measure the current in an electric circuit.

Ans: Ammeter

3) ___________ is used to measure potential difference .

Ans : Voltameter

4) If a wire carrying current is bent in the form of a circular loop, the magnetic field around the wire loop will be ___________ to the plane of the wire.

Ans : perpendicular

5) Ampere’s law concerned with the force on a wire carrying a current in a ________ field.

Ans : magnetic

6) Two parallel wires carrying current in the same direction _______ each other.

Ans : attract

7) Two parallel long conductors carrying current in the opposite direction will ________

Ans : repel

PRINCIPLE OF WORKING OF AN ELECTRIC MOTOR:

1) Electric motor converts  electrical energy into _______ energy

Ans : mechanical

2)The rectangular coil and iorn core in electric motor constitute_____

Ans : armature

3) RPM stands for _________

Ans : rotations per minutes

4) An ___________ consists of a rectangular coil of permanent magnet two metallic half-rings and an energy source.

Ans: electric motor

5) Current carrying rectangular coil behaves as a __________

Ans: magnet

6) A current carrying coil is subjected to a magnetic force, which rotates the coil imparting it a ______ energy.

Ans : kinetic

7) If the coil is made to rotate continuously, electric energy is converted into mechanical energy such an arrangement is called an _______

Ans : electric motor

8) Commutator is a device to reverse the direction of the _________

Ans : current

9) The commutator rotates with the ________

Ans : Shaft

10) A.C. stands for _______

Ans : Alternating Current

11) In A.C. motor , there is no need for a ______ to reverse the current.

Ans: commutator

12) A D.C. motor can have a efficiency less than _______

Ans : one

ELECTRO-MAGNETIC INDUCTION: 

1) Large amount of electricity is produced with the help of machines called ________ 

Ans : dynamos or generators

2) Dynamo converts mechanical energy into _______

Ans : electrical energy

3) A relative motion of a magnet and a coil induces _____ in the coil

Ans : induced

4) The moving magnet at higher speed causes the magnetic ________

Ans : flux

5) Dynamo works on the principle of electromagnetic ________

Ans : induction

6) The electricity that is supplied to our houhold appliance is generated by dynamos at _______

Ans : hydroelectric stations

7) The phenomenon of electromagnetic induction was discovered by ________

Ans : Faraday

8) A magnetic is moved inside a coil of wire with its south pole moving inside the coil.  Then the current flows through the coil in the ______ direction.

Ans : clockwise

9) A magnet is moved inside a coil of wire with its north pole moving inside the coil. Then current flows through the coil in the ____ direction.

Ans : anticlockwise

10) An A.C. current is one which varies periodically with time reversing the direction every _____ cycle.

Ans : half

11) Rapid rotating of the armature in the dynamo generates current or voltages in the external circuit whose direction  alternates in each half cycle. Such current are called ________

Ans: alternating current

12) The phenomenon of mutual inductance is utilized in the development of an electrical device called _________

Ans: Transformer

13) A transformer is an electric device which either increases or decreases the magnitude of an _____ voltage by utilizing the phenomenon of electromagnetic induction.

Ans : alternating

14) A transformer works on the principle of _____ using mutual inductance of two coils.

Ans : electromagnetic induction

15) All houses or industries are connected in ____ in main supply.

Ans: parallel

16) The transformer with number of turns in the secondary coil smaller than that in the primary coil is called ______ transformer

Ans : Step-down

17) The transformer with number of turns in the secondary coil larger than that in the primary coil is called _____ transformer

Ans : step – up

18) Power transmission is carried out in the form of high voltage and ______ current, so that energy losses are reduced.

Ans : low

19) A transformer uses ______ to minimize power losses

Ans : iron core

20) In a strep-up transformer , voltage in the secondary coil increases and current ______

Ans : decreases

21) A transformer works on _____ circuits only.

Ans : A.C.

22) In an ideal transformer the input power is equal to ________

Ans : output power

23) The efficiency of a transformer is always less than _______

Ans : one

24) A choke coil has low inductance and ______ resistance

Ans : high

25) Domestic  supply of voltage is ______

Ans : 220 volts

26) ________ transmission is carried out in the form  of high voltage and low current.

Ans : power

27) The bulk of electricity is generated at  ________ power stations

Ans hydro electric

28) In power stations, mechanical energy is converted into ______ energy

Ans : electric

29) The commercial generators work on the principle of a ________

Ans: dynamo

30) Electricity is transmitted by a _____ system using pylon.

Ans : grid

31) Pylons are high structures of towers to which _____ lines are connected

Ans : high tension or H.T.

32) A net work of H.T. supply system in a region is called a ____ grid

Ans : power

33) In a step down transformer the current _______

Ans : increases

34) For making core of a transformer , the material is ______

Ans : soft iron

35) A transformer uses _____ core to minimize power loss

Ans : iron

36) The feeder stations in A.P. are ______

Ans : 150

37) The 33 K.V. is supplied to about ____ stations

Ans : 50

38) The power transmission utilizes _____ at different points on the transmission lines.

Ans : transformer

39) Eddy currents are set up in  a metallic block kept to varying ______ field.

Ans : magnetic

40) Energy loss due to eddy currents can be minimized in a transformer by laminating the core of the ________.

Ans : transformer

41) A choke is a coil of _________

Ans: Pure inductance

42) A choke is used to limit an __________

Ans : alternating current

43) Which type of  current can be transmitted over a long distances easily______

Ans : A.C.

44) For electroplating we can use _______

Ans : D.C.

45) _______ is used to convert mechanical energy into electrical energy

Ans : Dynamo or generator

46) A relative motion of a magnet and coil induces ______ in the coil

Ans : current

47) The principle of working of a dynamo is the law of _______

Ans : Electromagnetic induction

48) A _____ is a electrical device which either increases or decreases the magnitude of an alternating voltage.

Ans : transformer

49) A transformer works on the principle of ______

Ans : electromagnetic induction

50) An example of ohmic conductor is ______

Ans : copper wire

51) If 12 amperes current is passed through a wire for 10 seconds, the amount of charge is ______

Ans: 120 coulombs 

52) A charge of 480 coulombs is flowing in 2 minutes through an electric bulb. The current flowing in the bulb is _____

Ans : 4 amp

53) On every day a 60W bulb is used for 4 hours.  The amount of energy utilized in 30 days in kilowatt hours is _______

Ans : 7.2 

54) An immersed heater is connected to a line of 220 volts for half an hour.  If it draws a current of 16.8 A, the heat developed by it is ______

Ans : 1.584 x 106 calories

55) The conversion of an A.C. into D.C. can be achieved by _________

Ans : a rectifier  circuit

56) A transformer works on the principle of ______ induction.

Ans : mutual

57) A transformer uses iron core to ______

Ans : minimize losses

58) The unit of self inductance is _________

Ans : Henry