Physics MCQ (Multiple Choice Questions) - SchoolingAxis

Physics MCQ (Multiple Choice Questions)

 Que- A sensitive galvanometer gives full-scale deflection with 100 mV. If the resistance of the galvanometer is 50 Ohm the maximum current that can flow through safely is  

a. 2.0 mA 

b. 20 mA 

c. 200 mA 

d. 0.2 mA 

Answer- 2.0 mA

Que- An ammeter measures the total current flowing through a circuit when it is connected  

a. in series with the circuit  

b. in parallel with circuit 

c. in series with any of the parallel resistances in the circuit 

d. in parallel with any of the series resistances in the circuit 

Answer- in series with the circuit 

Que- Coil of a galvanometer is suspended in a radial magnetic field so that the deflecting torque on the coil is always  

a. BINA cosa 

b. BINA sina 

c. BINA tana 

d. BINA 

Answer- BINA

Que- A galvanometer basically is an instrument used to  

a. detect current in a circuit 

b. measure current flowing through a circuit 

c. measure voltage across a circuit 

d. measure potential difference between two points in a circuit 

Answer- detect current in a circuit

Que- The effective way to increase the sensitivity of a moving coil galvanometer is to  

a. use a very long and fine suspension 

b. use a coil of very large area 

c. use a coil with very large number of turns 

d. use a very strong magnetic field 

Answer- use a very strong magnetic field

Que- A wheat stone bridge is said to be balanced when  

a. maximum current flows through the galvanometer branch 

b. minimum current flows through the galvanometer branch 

c. potential difference across galvanometer branch is maximum 

d. potential difference across galvanometer branch is zero 

Answer- potential difference across galvanometer branch is zero

Que- When an electron moving with a uniform speed in a vacuum enters a magnetic field in a direction perpendicular to the field the subsequent path of the electron is  

a. a straight line parallel to the field 

b. a parabola in a plane perpendicular to the field 

c. a circle in a plane perpendicular to the field 

d. a straight line along its initial direction 

Answer- a circle in a plane perpendicular to the field

Que- A particle of mass m charge q and speed V enters a uniform magnetic radius r. The radius r of the circle is  

a. independent mass m 

b. directly proportional to m 

c. directly proportional to q 

d. directly proportional to B 

Answer- directly proportional to m

Que- Galvanometer is a very sensitive device with  

a. very low damping 

b. very high damping 

c. no damping at all 

d. radial field disintegration 

Answer- very low damping

Que- Which one of the following methods would be able to increase the sensitivity of a moving coil galvanometer ? 

a. connect a shunt across the coil 

b. use a coil of smaller cross sectional area 

c. use a coil having less number of turns 

d. use spiral springs whose force constant is small 

Answer- use spiral springs whose force constant is small

Que- Heating a magnet will  

a. weaken it 

b. strengthen it 

c. reverse its polarity 

d. demagnetize it completely 

Answer- weaken it

Que- If a current carrying solenoid is suspended freely it will  

a. be rotating 

b. come to rest in N-S direction 

c. vibrating like galvanometer needle 

d. comes to rest after rotation 

Answer- come to rest in N-S direction

Que- The practical illustration of the phenomenon of mutual induction is  

a. A . C generator 

b. D . C dynamo 

c. induction coil 

d. transformer 

Answer- transformer

Que- Weber is the unit of  

a. Magnetic field intensity 

b. magnetic induction 

c. magnetic flux 

d. self-inductance 

Answer- magnetic flux

Que- Current produced by moving the loop of wire across a magnetic field is called  

a. A . C current 

b. D . C current 

c. induced current 

d. mean square current 

Answer- induced current

Que- emf induced in a circuit according to Faradays law depends on the  

a. maximum magnetic flux 

b. rate of change of magnetic flux 

c. change in magnetic flux 

d. initial magnetic flux 

Answer- rate of change of magnetic flux

Que- cmf generated by A . C dynamo depends upon  

a. number of turns in the coil 

b. magnetic field strength 

c. frequency of rotation 

d. all of above 

Answer- all of above

Que- An alternating current or voltage  

a. fluctuates off and on 

b. varies in magnitude alone 

c. changes its direction again and again 

d. changes its magnitude continuously and reverses its direction of flow after regularly recurring intervals. 

Answer- changes its magnitude continuously and reverses its direction of flow after regularly recurring intervals.

Que- A dynamo converts  

a. mechanical energy into electrical energy 

b. electrical energy into mechanical energy 

c. magnetic energy into mechanical energy 

d. magnetic energy into electrical energy 

Answer- mechanical energy into electrical energy

Que- Which one of the following functions like a motor? 

a. galvanometer 

b. ammeter 

c. voltmeter 

d. all of above 

Answer- all of above

Que- A . C cannot be used for  

a. producing heat 

b. producing light 

c. magnetizing and electroplating 

d. all the above 

Answer- magnetizing and electroplating

Que- Which of the following works on torque on the current carrying conductor placed in magnetic field. 

a. galvanometer 

b. ammeter 

c. voltmeter 

d. all of the above 

Answer- all of the above

Que- Self inductance of a coil depends upon  

a. current flowing 

b. number of turns per unit length 

c. voltage produce 

d. all 

Answer- all

Que- If the coil is wound on an iron core the flux through it will  

a. decrease 

b. become zero 

c. remain the same 

d. increase 

Answer- increase

Que- Energy stored in a magnetic field is given by  

a. LI2 

b. L2I/2 

c. LI2/2 

d. IL2 

Answer- LI2/2

Que- Inductors acts as a short circuit for  

a. AC 

b. DC 

c. Both (a) and (b) 

d. none of these 

Answer- DC

Que- For electroplating we use  

a. A D . C source 

b. an A . C source 

c. any source 

d. all of the above 

Answer- A D . C source

Que- Which of the following uses electric energy and does not convert it into any other form? 

a. transformer 

b. motor 

c. D . C generator 

d. A . C generator 

Answer- transformer

Que- The only difference between construction of D . C generator and A . C generator is that of  

a. carbon brushes 

b. coil 

c. commutator 

d. magnetic field 

Answer- commutator

Que- A . C and D . C have the same  

a. effect in charging a capacitor 

b. effect in charging a battery 

c. effect while passing through an inductance 

d. heating effect through a resistance 

Answer- heating effect through a resistance

Que- If the secondary coil has Ns turns and the primary Np turns the relation between secondary and primary voltages is given by  

a. Vs/Vp = Np/Ns 

b. Vs/Vp = Ns/Np 

c. Vp/Vs = Ns/Np 

d. Vp/Vs = Np/Ns 

Answer- Vs/Vp = Ns/Np

Que- Power loss in actual transformer is due to  

a. Small output 

b. Eddy currents and magnetic hysterias 

c. Soft iron core 

d. Back emf 

Answer- Eddy currents and magnetic hysterias

Que- A metal rod of 25 cm length is moving at a speed of 0.5/sec in direction perpendicular to 0.25T magnetic field. Emf produced in the rod is  

a. 0 volt 

b. 3.125 volt 

c. 31.25 volt 

d. 0.03125 volt 

Answer- 0.03125 volt

Que- The emf induced in a coil by a changing magnetic flux may have unit as  

a. ms-1A 

b. ms-2A-1 

c. kgms2A-1 

d. kgm2s-1A-1 

Answer- kgm2s-1A-1

Que- The emf induced in a conductor of unit length moving with unit velocity at right angles to a magnetic field is equal to  

a. Magnetic flux density 

b. Torque 

c. Mutual induction 

d. Motional emf 

Answer- Magnetic flux density

Que- The self-inductance of a solenoid is increased when a soft iron core is inserted into it. This is because the soft iron core 

a. Decreases the resistance of the solenoid 

b. Reduces the effect of eddy current 

c. Improves the flux linkage between the turns of the coil 

d. Increases the mutual inductance between the solenoid and the core 

Answer- Improves the flux linkage between the turns of the coil

Que- A small coil lies inside a large coil. The two coils are horizontal concentric and carry currents in opposite directions. The large coil will experience  

a. A torque about horizontal axis 

b. A torque about vertical axis 

c. An upward force along the axis 

d. No resultant force 

Answer- No resultant force

Que- An aeroplane of wingspan 10m flies from the equator towards the North Pole. The wings are perpendicular to the vertical component of the earths magnetic field (B = 4x10-5T). At maximum speed an emf of 96mV is induced across the wing tips. The maximum speed of the aeroplane is  

a. 150msec-1 

b. 384msec-1 

c. 38.4msec-1 

d. 200msec-1 

Answer- 384msec-1

Que- A . C can not be used for  

a. producing heat 

b. producing light 

c. Magnetizing iron 

d. Producing magnetic field 

Answer- Magnetizing iron

Que- Non inductive resistances are used in decreasing  

a. Mutual inductance 

b. Self inductance 

c. Magnetic fields 

d. Heating effect 

Answer- Self inductance

Que- Magnetic compass needle will be deflecting if it is kept near  

a. Static charge 

b. Soft iron 

c. Semi-conductor 

d. Accelerating charge 

Answer- Accelerating charge

Que- Long distance transmission is easy for  

a. D . C voltage 

b. A . C voltage 

c. Half A . C voltage 

d. Half D . C voltage 

Answer- A . C voltage

Que- Which one of the following devices does not function like an electric motor? 

a. Galvanometer 

b. Ammeter 

c. Voltmeter 

d. Transformer 

Answer- Transformer

Que- The out put voltage of a transformer is 3 times the input voltage then turns ratio will be  

a. 3-Jan 

b. 3 

c. 1 

d. 6 

Answer- 3

Que- For long distance transmission the transformer used is  

a. Step down 

b. Input voltage and output voltage remain same 

c. Step up 

d. Amplifier is used 

Answer- Step up

Que- An electric current induced within the body of a conductor when that conductor either moves through a non uniform magnetic field or in a region where there is a change in magnetic flux is called  

a. Induced current 

b. Eddy current  

c. Back emf 

d. None of the above 

Answer- Eddy current 

Que- Lagging of changes in the magnetization of a substance behind changes in the magnetic field as the magnetic field is varied is known as magnetic  

a. Retaintivity 

b. Permeability 

c. Flux 

d. Hysteresis 

Answer- Hysteresis

Que- Transformer works on the principle of  

a. Lenzs law 

b. Faradays law 

c. Mutual induction 

d. Law of conservation of power 

Answer- Mutual induction

Que- When the motor is at its maximum speed then back emf will be  

a. Maximum   

b. Zero 

c. Intermediate values 

d. No back emf 

Answer- Maximum  

Que- An alternating current or voltage  

a. fluctuates off and on 

b. varies in magnitude alone 

c. changes its direction again and again 

d. changes its magnitude harmonically and reverses its direction of flow after regularly recurring intervals. 

Answer- changes its direction again and again

Que- A changing magnetic flux produces around itself an induced  

a. Magnetic field 

b. Electric field 

c. Electromagnetic force 

d. Artificial gravitational field 

Answer- Electromagnetic force

Que- Electromagnetic waves travel in free space with the speed of  

a. ?-rays 

b. Positive rays 

c. Cathode rays 

d. More than sound waves 

Answer- ?-rays

Que- The direction of propagation of an electromagnetic waves is  

a. Perpendicular to electric field 

b. Perpendicular to both electric and magnetic field 

c. Perpendicular to magnetic field 

d. Parallel to electric and magnetic field 

Answer- Perpendicular to both electric and magnetic field

Que- An electromagnetic wave consists of  

a. Electric and magnetic fields moving parallel to each other 

b. Magnetic field moving with velocity of light in space 

c. Electric field moving with velocity of light 

d. Electric and magnetic fields moving perpendicular to each other 

Answer- Electric and magnetic fields moving perpendicular to each other

Que- Electromagnetic waves transport  

a. Energy 

b. Momentum 

c. Mass 

d. Heat 

Answer- Energy

Que- Waves emitted from the antenna are  

a. Sound waves 

b. Electromagnetic waves 

c. Radio waves 

d. Modulated waves 

Answer- Electromagnetic waves

Que- Electromagnetic waves emitted from antenna are  

a. Stationary 

b. Longitudinal 

c. Transverse 

d. All the above 

Answer- Transverse

Que- If capacitance of L-C circuit is made four times then frequency of the circuit becomes  

a. Twice 

b. One half 

c. Four times 

d. None 

Answer- One half

Que- A capacitor of capacitance 30 Degree F is charged by a constant current of 10mAIf initially the capacitor was uncharged what is the time taken for the potential difference across the capacitor to reach 300V? 

a. 0.9sec 

b. 15 sec 

c. 1.5x105sec 

d. 0.9x102sec 

Answer- 0.9sec

Que- The value of the steady current which when flowing through the same resistor produces heat at the same rate as the mean rate of heat produced by the alternating current is  

a. Average current 

b. Sinusoidal current 

c. r.m.s current 

d. Net current 

Answer- r.m.s current

Que- To find the r.m.s value of an alternating current mathematically we need to have  

a. Mean value of I2 

b. Square root of mean value of I2 

c. Square root of I2 

d. Square of 1/2 

Answer- Square root of mean value of I2

Que- An alternating current of r.m.s value of 4.0 A and frequency 50Hz flows in a circuit containing 10 ohm resistor. The peak current is then  

a. 20A 

b. 20.66A 

c. 6.66A 

d. 5.66A 

Answer- 5.66A

Que- pure resistor circuit the voltage and current are  

a. Lagging each other 

b. They are at 90 Degree phase difference 

c. They have zero phase difference 

d. No phase difference 

Answer- They have zero phase difference

Que- If a glass plate is inserted in between the plate of a capacitor in series with a lighted bulb the brightness of the bulb  

a. Remains same 

b. Brightness increases 

c. Brightness decreases 

d. No light 

Answer- Brightness increases

Que- A pure variable resistor is connected in series with a pure capacitor of fixed capacitance. The impedance of the circuit  

a. Remains   

b. Becomes infinite 

c. Becomes zero 

d. Increases 

Answer- Increases

Que- Ammeter connected in an AC circuit measures  

a. Exact value of current 

b. rms value of current 

c. Net value of current 

d. Peak value of current 

Answer- rms value of current

Que- When a pure inductor of inductance L and a pure capacitor of capacitance C are connected in parallel to a sinusoidal potential difference V the potential difference across both L & C will be  

a. Same 

b. Different 

c. At L will be more than at C 

d. At L will be less than at C 

Answer- Same

Que- What is the self inductance of a coil in which an induced emf of 2V is set up when the current changes at the rate of 4 As-1? 

a. 0.5 mH 

b. 0.5H 

c. 2.0H 

d. 8.0H 

Answer- 0.5H

Que- A choke is used as a resistance in  

a. DC circuit 

b. AC circuits 

c. Both AC and DC circuit 

d. Full wave rectifier circuit 

Answer- AC circuits

Que- Choose the correct statement. In the case of AC circuit ohms law holds for  

a. Peak values of voltage and current 

b. Effective values of voltage and current 

c. Instantaneous values of voltage and current 

d. All of the above 

Answer- All of the above

Que- The phase angle between the voltage and the current in an AC circuit consisting of a resistance is  

a. Zero 

b. 45 Degree 

c. 90 Degree 

d. 180 Degree 

Answer- Zero

Que- In an LCR series circuit, if V is the effective value of the applied voltage VR is  the voltage across R VL is the effective voltage across L & Vc is the effective voltage across C then  

a. V = VR+VL+VC 

b. V2 = VR2+VL2+VC2 

c. V2 = VR2+(VL-VC)2 

d. V2 = VL2+(VR-VC)2 

Answer- V2 = VR2+(VL-VC)2

Que- Two identical coaxial circular loops carry equal currents in the same direction. If the loops approach each other the current in  

a. Each increases 

b. Each decreases 

c. Each remains the same 

d. One increases whereas that in the other decreases 

Answer- Each decreases

Que- An inductor may store energy in  

a. its electric field  

b. its coils 

c. its magnetic field 

d. both electric and magnetic fields 

Answer- its magnetic field

Que- Which of the following substances posses the highest elasticity? 

a. Rubber 

b. Steel 

c. Glass  

d. Copper 

Answer- Steel

Que- What is the SI unit of modulus of elasticity of substance? 

a. Nm-2 

b. Jm-2 

c. Nm-1 

d. Being a number it has no unit. 

Answer- Nm-2

Que- Which one of the following physical quantities does not have the dimensions of force per unit area? 

a. Stress 

b. Strain 

c. Youngs modulus 

d. Pressure 

Answer- Strain

Que- A rubber cord of cross-sectional area 2cm2 has a length of 1m. When a tensile force of 10N is applied the length of the cord increases by 1cm. What is the youngs modulus of rubber? 

a. 2x108 Nm-2 

b. 5x106 Nm-2 

c. 0.5x10-6 Nm-2 

d. 0.2x10-6Nm-2 

Answer- 5x106 Nm-2

Que- A wire suspended vertically from one end is stretched by attaching a weight of 20N to the lower end. The weight stretches the wire by 1mm. How much energy is gained by the wire? 

a. 0.01J 

b. 0.02J 

c. 0.04J 

d. 1.0J 

Answer- 0.01J

Que- A certain stress applied to an elastic material produces a certain strain in it. If the elastic limit is not exceeded the energy gained per unit volume of the material is given by  

a. Stress/strain 

b. (stress/strain) 

c. Stress x strain 

d. (Stress / strain) 

Answer- (Stress / strain)

Que- A uniform steel wire of length 4m and area of cross-section 3x10-6m2 is extended by 1mm by the application of a force. If the youngs modulus of steel is 2x1011 Nm-2 the energy stored in the wire is  

a. 0.025J 

b. 0.50J 

c. 0.75J 

d. 0.100J 

Answer- 0.75J

Que- The ration stress to strain in youngs modulus of the material then tension is  

a. Directly proportional to extension. 

b. Directly proportional to strain. 

c. Directly proportional to square of amplitude. 

d. Inversely proportional to extension. 

Answer- Directly proportional to extension.

Que- Materials that undergo plastic deformation before breaking are called 

a. Brittle 

b. Ductile 

c. Amorphous 

d. Polymers 

Answer- Ductile

Que- A wire is stretched by a force F which causes an extension  

a. The energy stored in the wire is  

b. The extension of the wire is proportional to the force applied 

c. The weight of the wire is negligible 

d. The wire is not stretched beyond its elastic limit 

Answer- The energy stored in the wire is 

Que- A wire obeys Hooks law is of length 11 when it is in equilibrium under a tension F 

a. Its length becomes 12 when the tension is increased to F 

b.  The energy stored in the wire during this process is  

c. (F1+F2) (121+122) 

d. (F1+F2) (122-112) 

Answer- (F1+F2) (12-11)

Que- Formation of large molecule by joining small molecules is  

a. Fusion 

b. Polymerization 

c. Crystallization 

d. Subtraction 

Answer- Polymerization

Que- Any alteration produced in shapes length or volume when a body is subjected to some external force is called  

a. Stiffness 

b. Toughness 

c. Extension 

d. Deformation 

Answer- Deformation

Que- The energy band occupied by the valence electrons is called  

a. Energy state 

b. Valence band 

c. ve energy state 

d. conduction band 

Answer- Valence band

Que- The curie temperature is that at which 

a. Semi-conductor becomes conductors 

b. Ferromagnetic becomes paramagnetic 

c. Paramagnetic becomes diamagnetic 

d. Metals become super conductor 

Answer- Ferromagnetic becomes paramagnetic

Que- A ferromagnet will become fully magnetized at  

a. High voltage A . C 

b. Low voltage A . C 

c. Alternating current at its peak value 

d. D . C current at peak value 

Answer- Alternating current at its peak value

Que- Coercive force is the force which opposes  

a. Demagnetization 

b. Breakage 

c. Extension 

d. Surface cracking 

Answer- Demagnetization

Que- Materials in which valence electrons are tightly bound to their atoms at low temperature are called  

a. Semi conductor 

b. Super conductors 

c. Insulators 

d. Conductor 

Answer- Insulators

Que- The bulk properties of materials such as their mode of fracture can be related to their  

a. Polymerization 

b. Cleavage 

c. Microstructure 

d. Dislocation 

Answer- Microstructure

Que- The angular position of cells remains the same for a sample of a crystal. This property is called  

a. Isotropy 

b. Cleavage 

c. Homogeneity 

d. The external symmetry of form 

Answer- The external symmetry of form

Que- The breaking of crystals along definite direction is called  

a. Cleavage 

b. Symmetry 

c. Isotropy 

d. Homogeneity 

Answer- Cleavage

Que- If the density of atoms remain same along any direction in a crystal is called  

a. Symmetry 

b. Homogeneity 

c. Isotropy 

d. Cleavage 

Answer- Homogeneity

Que- In simple cube one atom or molecule lies at its  

a. Force corners 

b. Nine corners 

c. Eight corners 

d. Six corners 

Answer- Eight corners

Que- The band theory of solids explains satisfactorily the nature of  

a. Electrical insulators alone 

b. Electrical conductors alone 

c. Electrical semi conductors alone 

d. All of the above 

Answer- All of the above

Que- A vacant or partially filled band is called  

a. Conduction band 

b. Valence band 

c. Forbidden band 

d. Empty band 

Answer- Conduction band

Que- A completely filled band is called  

a. Conduction band 

b. Valence band 

c. Forbidden band 

d. Core band 

Answer- Core band

Previous Post Next Post