Basic Physics Questions and Answers

he electron concentration in an n type semiconductor is the same as hole concentration in a p type semiconductor An external field electric is applied across each of them Compare the currents in them 1 2 4 current in n type current in p type No current will flow in p type current will only flow in n type current in n type current in p type current in p type current in n type

An ideal gas is taken from the state A pressure Po volume Vo to the state B pressure P 2 volume 2V along a straight line path in the P V diagram Select the correct statement s from the following 1993 A The work done by the gas in the process A to B exceeds the work that would be done by it if the system were taken from A to B along the isotherm B In the T V diagram the path AB becomes a part of the parabola C In the P T diagram the path AB becomes a part of hyperbola D In going from A to B the temperature T of the gas first increases to maximum value and then decreases

Two small satellites move in circular orbits around the earth at distance r and r Ar from the centre of the earth Their time periods of rotation T and T AT Ar r AT T A AT 3 4 5 Ar C AT 3 Ar Ar B AT T4 IDYAT Ar

Gurukripa CAREER INSTITUTE 5 Current through the ideal diode is 1000 1 zero 2 20 A 3 4 20 A 50 6 Output W is given by SV 5 1 2 20 A A 20 50 6 ft W P 9 EMI AC Electronics EM Wav D 1000 SV

The speed of a wave in a certain medium is 1080 m s If 1800 waves pass over a certain point of the medium in 30 seconds then wavelength of the wave is O 12 m 016 m 0 18 m 43 28 O 22 m

concentration in an semiconductor is the same as his conte in a p type semiconductor An external electric is applied across each of them Com the currents in them 1 2 8 current in n type current in ptpe No current will flow in p type curren only flow in n type current

questions Each question has 4 choices 1 2 3 and Read More A cylinder is wrapped around its lateral surface by a rope as shown in the figure The rope is moved upwards such that cylinder does not fall from its initial position Initially it was at rest What is the acceleration of the rope mgv g 2 g

The ratio of the energy released by 4kg of hydrogen at sun by fusion process to 23 5 kg of 235U in the nuclear reactor by fission process is Assume energy released per fusion is 26 MeV and that per fission is 200 MeV A 5 13 13 10 B 1 26 D 10 13

of SS ne ed ne al ar th and hat the 21 Three pieces of wood having 10mm x 10mm square cross section are glue to gather and to the foundation as shown in fig If the horizontal forces P is 3 kN the stress developed at the joint is a 3 Mpa c 30 Mpa 10 10 10 a c b 3 Gpa d 30 Gpa 100mm 22 Rails are laid with their adjacent ends 3mm apart when the temperature is 30c The length of each rail is 10m Young s modulus for the material is 200 Gpa Temp at which Adjacent end will contact Take a 10 x 10 6C 0 001 rad 0 005 rad P b 0 002 rad d None 23 The max shearing stress in a piece of metal is 200 Mpa If modulus of rigidity two stre dev a 28 c 26 If a ste the a c 27 In su a c If CC CC a C 29 In SL C

Potentiometer can be used to measure emf of any cel more effectively than voltmeter because O It works on deflection method It use a large current to measure emf It draws no current from cell while measuring its emf hr min It is based on Wheatstone bridge

26 A freely falling body of mass m in the tth second of its fall loses potential energy by C mg t 1 27 B ma t 1 The energy of an electron in the nth orbit of hydrogen atom is A Proportional to n C Proportional to n D mg 2 2t 1 B Inversely proportional to n D Inversely proportional to n

6 Two point charges QA 5 C and QB 5uC are located at A and B separated by 0 2m in vacuum a What is the electric field at the midpoint o of the line joining the charges b If a negative test charge of magnitude 2n is placed at o what is the force experienced by the test charge 5 The plaged

An arrow leaves a certain bow with a speed of 30 m s a What is its maximum range b At what angle could the archer point the arrow if it is to reach a target of 70 m awy I A 92 m 25 degree B 92 m 65 degree both a and b none

0 180 three molecules of oxygen at 27 C have velocities 0 5 km s 1 km s nd 2 km s respectively Then their root mean square speed will be O 1 7 km s O 1 32 km s O 1 13 km s O 1 17 km s

4 not biased 4 In the given circuit the output Y becomes zero for the 3 f inputs Aa B C 1 A 1 B 1 C 0 2 A 0 B 1 C 1 3 A 0 B 0 C 0 4 A 1 B 1 C 1 AUG fua faria Y 34 B a fama fadx l fad A B C 1 A 1 B 1 C 0 2 A 0 B 1 C 1 3 A 0 B 0 C 0 4 A 1 B1 C 1

angle 8 with the x axis What is the force experienced by the dipole b The magnetic field through a coil having 500 turns and cross sectional area 0 20m changes from 0 02 Wb m to 0 6 Wb m at a uniform rate over a period of 0 01 second What will be the magnitude of induced emf In a hydrogen atom the electron and proton are bound at a distance of about 0 52 1

Two small pith balls with mass m each are suspended from same point using two identical insulating threads When the balls are given equal positive charge Q they hang in equilibrium as shown The charge on the left ball is slowly increased from Q to 20 Assume that its mass does not change Which of the following diagrams best represents Q the new equilibrium a c 20 20 0 0 0 Q b d 20 20 0 0 Q O 0

Assertion A piece of ice with a stone frozen inside it floats on water in a beaker When the ice melts the level of water in the beaker decreases Reason Density of stone is more than that of water a Both assertion and reason are true and reason is the correct explanation of assertion b Both assertion and reason are true but reason is not the correct explanation of assertion c Assertion is true but reason is false d Both assertion and reason are false

For the part of the circuit shown potential difference across AB is 5V 50 0 5V O 10 V O 25 V O 15 V 502 www wwww 2A 50

For a plane electromagnetic wave propagating in x direction which one of the following combination gives the correct possible directions for electric field E and magnetic field B respectively 1 2 3 j k j k A j k j k A itb i k

Two positive point charges of unequal magnitude are placed at a certain distance apart A small positive test charge is placed at null point then 1 The test charge is in unstable equilibrium 2 The test charge is in stable equilibrium 3 The test charge is in neutral equilibrium 4 The test charge is not in equilibrium

Figures below show a regular hexagon with pot charges placed at the vertices In which of th following arrangements the electric field at the cent of the hexagon is zero 54 4q 2 29 a IV c I 1 24 24 29 29 29 b III d II 11 IV 2q 9 9

A cell of internal resistance 100 is connected across resistor R The value of R is varied from 100 to 150 The power consumed by R O Increases continuously O Decreases continuously O First decrease then increases O First increases then decreases

a 2 b 3 c 4 More than One correct answer Type Questions 10 A swimmer swims in still water at a speed 5km hr He enters a 200 m wide river having river speed 4 km hr at point A and proceeds to swim at an angle of 127 with the river flow direc Another point B is located directly across A on the other side The swimmer lands on the other at point C from which he walks the distance CB with a speed 3 km hr The total In minutes in which he reaches from A to B is a 4 b 1 c 2 running upwards on the hill d 6

1 A circular loop of area 0 01m carrying a current of 10A is held with its plane perpendicular to a magnetic field of intensity 0 1T The torque acting on the loop is 1 Zero 2 0 01 Nm

Although the root mean square speed o f gas molecules is of the order of spee d of sound in that gas wet on opening a bottle of ammonia in one corner of a r oom its smell takes time in reaching th e other corner Why

A direct current flowing through the winding of long cylindrical solenoid of radius R produces a uniform magnetic field B inside it An electron enters into the solenoid along the radius between its turns at right angle to the solenoid axis with a speed v After a certain time the electron deflected by the magnetic field leaves the solenoid Find the time during which the electron moves in the solenoid O O O m eB tan 1 2e B 2m eB eBR my tan eBR mv tan Co eBR my

estion No 18 Phy Section A This section contains 35 SINGLE CORRECT TYPE questions Each question has 4 choices 1 2 3 and 4 out of which only one is Which among the following statement is correct O Natural convection occurs only in gravity free space O Natural convection can occur in space having gravity as well as gravity free space O Forced convection occurs only in space having gravity O Forced convection can occur in gravity free space

particle is hanging from a fixed point O by means of a string of length a There is a small nail Q in the same horizontal line with O at a distance b b a 3 from O Find the minimum velocity ith which the particle should be projected so that it may make a complete revolution around the ail without being slackened

Two charged particles Mand N enter a space of uniform magnetic field with same velocities perpendicular to the magnetic field The paths are as shown in figure Then X X M X X X N X X Charge of Mis greater than that of N The momentum of Mis greater than that of N Specific charge of Mis greater than that of N

30 In a universal testing machine during the testing of a specimen of original C S area 1 cm the max load applied was 7 5 tonnes and net area 0 6cm The ultimate tensile strength of specimen is a 12 5 t cm c 7 5 t cm b 10 0t cm d 3 5 t cm

A 2 V potentiometer is used to determine the internal resistance of a 1 5 V cell the balance point of the cell in the open circuit is 75 cm When a resistor of 10 Q is connected across the cell the balance point shifts to 60 cm The internal resistance of the cell is 1 5 Q 2 5Q 3 5 Q 4 5 Q

A man swimming down stream overcome a float at a point M After travelling distance D be back and passed the float at a distance of D 2 from the point M then the ratio of speed of s with respect to still water to the speed of the river will be a 2 b 3 c 4 More than One correct answer Type Questions d 2 5

In a photoelectric effect set up a point source of light of power 3 2 x10 W emits monoenergetic photons of energy 5 0 eV The source is located at a distance of 0 8 m from the centre of a stationar metallic sphere of work function 3 0 eV and of radius 8 x10 m The efficiency of photo electrons emission is one for every 106 incident photons Assume sphere is isolated and initially neutral and that photo electrons are instantly swept away after emission then A No of electrons emitted per second is 106 BY Time after which electron emission stops is 111 11 sec No of electrons emitted per second is 10 D Time after which electron emission stops is 11 11 sec

stion No 28 Phy Section A his section contains 35 SINGLE CORRECT TYPE questions Each question has 4 choices 1 2 3 and 4 out of which only one is correct ne V characteristics of a non ohmic device is shown in the figure Which region represents the negative resistance region mA B W V volt O OA AB BC

Ligh a symmetric glass prism If the critical angle for total reflection at the glass air interface is 420 the angle a of the prism for which the incident ray is totally reflected from both the rear faces of the prism satisfies A 84 B x 96 C 88 a 96 D 42 a 84

A uniform rope of length L and mass m hangs vertically from a rigid support A block of mass m is attached to the free end of the rope A transverse pulse of wavelength is produced at the lower end of the rope The wavelength of the pulse when it reaches the top of the rope is 22 The ratio is NEET 2016 1 m m m m m 2 m m M

a opposite to ar e opposite to or 00 Three long straight and parallel wires carrying currents are arranged as shown in the figure The wire C which carries a current of 50 A is so replaced that it experiences no force The distance of wire C from wire D is then UP CPMT a 9 cm o 5 am 15A b along ox d along oy 15A 15 x 10A b 7 cm

A smooth sphere A of mass m collides elastically with identical sphere B at rest The velocity of A before collision is 8 m s in a direction making an angle of 60 with the line of centres at the time of impact 4 The sphere A comes to rest after collision The sphere B will move with a speed of 8 m s after collision The directions of motion A and B after collision are at right angles The speed of B after collision is 4 m s

11 Two thin dielectric slabs of dielectric constants K and K K K are inserted between plates of a parallel plate capacitor as shown in the figure The variation of electric field E between the plates with distance d as measured from plate P is correctly shown by AIPMT 2014 1 3 O 0 TI K K d 2 tu 4

A uniform magnetic field with a slit system as shown in figure is to be used as a momentum filter for high energy charged particles With a field of B tesla it is found that the filter transmits a particle each of energy 5 3 MeV The magnetic field is increased to 2 3B tesla and deuterons are passed into the filter What is the energy of each deuteron transmitted by the filter 5 3 MeV 150 3 MeV 1500 3 MeV 14 02 MeV Oo o Source OOO O Deterctor

Two bodies of masses m and m2 are dropped from height h and h respectively They reach the ground in time t and t2 and strike the ground with velocity v and v respectively then 1 2 FIS Ov t V2t2 0 m h V Vm h

When the same amount of the solute P and Q are separately dissolved in 500g water the ATF values are 0 15K and 0 30K respectively If the molecular weight of P is 80 g mol then the molecular weight of Q is B 60 g mol E 160 g mol A 30 g mol D 45 g mol C 40 g mol

A 5 kg block is placed on top of a 10 kg block figure A horizontal force of 45 N is applied to the 10 kg block and the 5 kg block is tied to the wall The coefficient of friction between all moving surfaces is 0 1 Determine the tension in N in the string 5kg 10kg F 45N

A proton of mass 1 67 10 27 kg and charge 1 0 x 10 1 C is projected with a speed of 2 106 m s at an angle of 60 to the x axis If a uniform magnetic field of 0 104 T is applied along y axis the path of proton is helix with circular radius 0 2 m O radius 0 1 m O radius 0 5 m O radius 0 7 m

2 The rate of reaction becomes 2 times for every 10 C rise in temperature How the rate of reaction will increase when temperature is increased from 30 C to 80 C a 16 64 b 32 108039 d 128 6 The rate of elementary reaction A B increases by 16 10 of 4 is increased ten

Consider a heat ongine as shown in figure Q Q2 are heat added to T and heat removed from T2 in one cycle of engine W is the mechanical work done on the engine If W 0 then wh statement is true 1 2 3 4 Correct Answer 4 upottempted Q Q1 W Q Q 0 QW JOf T Q

The rate of a reaction get doubles when the temperature changes from 7 C to 17 C By what factor will it change for the temperature change from 17 C to 27 C a 1 81 c 1 91 b 1 71 d 1 76 27 17 19

When a block of iron floats in mercury at 0 C a fraction k of its volume is submerged while at the temperature 60 C a fraction k is seen to be submerged If the coefficient of volume expansion of iron is YFe and that of mercury is YHg then the ratio k k can be expressed as 1 60 Fe 1 60 Fe B 1 60YHg 1 60YHg A C 1 60YFe 1 60YHg D 1 60 Hg 1 60YFe 2001

ii A circuit containg a 80 mH inductor and a 60 F capacitor in series is connected to a 230 V 50Hz supply The resistance of the circuit i negligible a Obtain the current amptitude and rms values b Obtain the rms values of potential drops across each element c What is the average power transferred to the inductor