# Physics MCQ (Multiple Choice Questions) - SchoolingAxis

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

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

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

Que- Galvanometer is a very sensitive device with

a. very low damping

b. very high damping

c. no damping at all

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

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

Que- Weber is the unit of

a. Magnetic field intensity

b. magnetic induction

c. magnetic flux

d. self-inductance

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

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

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

Que- A . C cannot be used for

a. producing heat

b. producing light

c. magnetizing and electroplating

d. all the above

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

Que- Self inductance of a coil depends upon

a. current flowing

b. number of turns per unit length

c. voltage produce

d. 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

Que- Energy stored in a magnetic field is given by

a. LI2

b. L2I/2

c. LI2/2

d. IL2

Que- Inductors acts as a short circuit for

a. AC

b. DC

c. Both (a) and (b)

d. none of these

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

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

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

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

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

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

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

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

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

Que- A . C can not be used for

a. producing heat

b. producing light

c. Magnetizing iron

d. Producing magnetic field

Que- Non inductive resistances are used in decreasing

a. Mutual inductance

b. Self inductance

c. Magnetic fields

d. Heating effect

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

a. Static charge

b. Soft iron

c. Semi-conductor

d. 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

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

a. Galvanometer

b. Ammeter

c. Voltmeter

d. 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

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

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

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

Que- Transformer works on the principle of

a. Lenzs law

c. Mutual induction

d. Law of conservation of power

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

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

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

a. ?-rays

b. Positive rays

c. Cathode rays

d. More than sound waves

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

Que- Waves emitted from the antenna are

a. Sound waves

b. Electromagnetic waves

d. Modulated waves

Que- Electromagnetic waves emitted from antenna are

a. Stationary

b. Longitudinal

c. Transverse

d. All the above

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Que- An inductor may store energy in

a. its electric field

b. its coils

c. its magnetic field

d. both electric and magnetic fields

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

a. Rubber

b. Steel

c. Glass

d. Copper

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.

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

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

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

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)

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

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.

Que- Materials that undergo plastic deformation before breaking are called

a. Brittle

b. Ductile

c. Amorphous

d. Polymers

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)

Que- Formation of large molecule by joining small molecules is

a. Fusion

b. Polymerization

c. Crystallization

d. Subtraction

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

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

a. Energy state

b. Valence band

c. ve energy state

d. conduction 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

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

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

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

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

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

a. Symmetry

b. Homogeneity

c. Isotropy

d. Cleavage

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

a. Force corners

b. Nine corners

c. Eight corners

d. Six 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

Que- A vacant or partially filled band is called

a. Conduction band

b. Valence band

c. Forbidden band

d. Empty band

Que- A completely filled band is called

a. Conduction band

b. Valence band

c. Forbidden band

d. Core band