Basic Physics Questions and Answers

36 A cylindrical block of area of cross section A and of material of density r is placed in a liquid of density one third of density of block The block compresses a spring and compression in the spring is one third of the length of the block If acceleration due to gravity is g the spring constant of the spring is a p4g b 2p4g c 2p4g 3 d p4g 3 37 In A C circuit in which inductance and capacitance are joined in series current is found to be maximum when the value of inductance is 0 5 H and the value of capacitance is 8 F The angular frequency of applied alternating voltage will be a 400 Hz c 2 10 Hz b 5000 Hz d 500 Hz 38 Angle between magnetic meridian and geographical meridian is called a angle of dip b angle of declination c angle of depression d both a and b 39 Heat is required to change 1 kg of ice of 20 C into steam Q is the heat needed to warm the ice from 20 C to 0 C Q is the heat needed to melt the ice Q is the heat needed to warm the water from 0 C to 100 C and Q is the heat needed to 41 vaporize the water Then The graphical representation of the above process is shown is P 12Poy 4 7Po V Vo 2P P4 2Po P 2P P 2Po 2V V 2V0 Vo 2V V V 2V V A current carrying wire in the neighbourhood produces a Q4 Q3 Q Q b QQ Q Q c Q Q Q3 Q d Q Q Q Q d electric field only 40 The P V equation for a process of an ideal gas is 42 10g of ice at 0 C is mixed with 100 g of water at given by 50 C What is the resultant temperature of mixture a 31 2 C P c 36 7 C a electric and magnetic field b magnetic field only c no field b 32 8 C d 38 2 C

43 Which of the following correctly describes the magnetic field of a long straight wire 1 The field consists of straight lines perpendicular to the wire 2 The field consists of straight lines parallel to the wire 3 The field consists of radial lines originating from the wire 4 The field consists of concentric circles centred on the wire

A long rectangular slab of transparent medium is placed on a horizontal table with its length parallel to x axis and width parallel to the y axis as shown in diagram A ray of light travelling in air makes a grazing incidence on the slab The refractive index N of medium varies as N 2x The path of light ray is given by light ray 1 y 2log x n 1 2 y 0 X

Uniform magnetic field Bo exists in circular region a r 2a A charge particle q m is projected from a 0 with velocity voi Maximum value of vo so that particle does not exit the magnetic field region is xxx X x vx X x x 2a X X X X X X x x a X X X X X X x x qB a m X X 4 gBoa 3 m X X

nimum kinetic energy of the particle 59 The potential energy of a particle of mass 0 1 kg where x is in metres Choose the wrong option moving along the X axis is given by U 5x x 4 J b The particle executes simple harmonic motion a The speed of the particle is maximum at x 2 m c The period of oscillation of the particle is TC 5 d All are correct S

1 When speed of a body is zero it is considered to be at 2 For the force to act the two bodies must 3 By applying force in the direction opposite to the direction of the motion of a body we can its speed and the wheel slows down or stops a moving vehicle different parts of the rotating machine get damaged with time replacement 3 State whether the following statements are true T or false F Correct the false statements 1 The force acting on a body increases the mass of the body 2 Force can change the direction of motion 4 Friction between the 6 5 Friction causes wastage of As friction produces and need 3 If the applied force is not enough the object may not move 4 Less force will be required to move a heavier body than a lighter one 5 Friction causes wear and tear of the surfaces in contact 6 Only solid surfaces experience friction Choose the correct option 1 Which of the following is an effect of force a Starts motion c Stops motion 2 Which of the following is not a unit of force a gram force b dyne 3 Kneading dough shows which effect of force a change in speed c change in shape and size 4 Which of the following is not an effect of friction a To produce heat c To cause wear and tear of the surfaces 5 Which of the following is not a type of friction a Rolling friction b Static friction 6 Friction can be reduced by a using ball bearings b polishing b Changes the direction of motion d All of them c joule b change in direction d change in mass b To increase the speed of the body d To oppose the motion of the body c Slowing friction d newton c streamlining d Sliding friction d all of them

V k surface of a non viscous liquid of density less than the density of ball The motion of the ball is a SHM periodic but not SHM c not periodic d SHM for half a period and non periodic for rest half of the period SUPE

12 A thin semicircular ring of radius r has a positive charge q uniformly distributed over it The net electric field E at centre O is 9 2n E b 47 d 2n 7 j

1 When speed of a body is zero it is considered to be atest 2 For the force to act the two bodies must 3 By applying force in the direction its speed 4 Friction between the 5 Friction causes wastage of 6 As friction produces and need with each other opposite to the direction of the motion of a body we can and the wheel slows down or stops a moving vehicle different parts of the rotating machine get damaged with time replacement

Can t understand the question The values are to be remembered Plz Explain Which is correct for F CI Question Type Single Correct Type 1 2 3 4 IPF IPCI EAF EACI IPF IPCI EAF EACI IPF ENF IPCI ENCI All Asked by 3471507 aesl id Standard XII Stream NEET Jul 27 202 11 16 Add your responses Type Text Type your answer here OR you can upload an attachment from the option below

To reach your school at 10 30am let you start at 10 00am first you move 800 m towards East then 600m towards North and finally 200m towards West Then net displacement is 1 600i 6003 m 3 5001 5501 m 2 6001 6003 m 4 700 6503 m

46 The sound of thunder is heard 7 sec after a flash of lightning If the speed of sound in air is 330m sec the lightning flash occured at a distance of A 231 Km B 23 1 Km C 2 31 Km D 231 Km Mass of an oxygen molecule is 16 times that of a hydrogen molecule The ratio of the total kinetic energy of the molecules of one mole of oxygen to that of one mole of hydrogen both kept at 100 C is A 16 1 B 4 1 C 1 1 D 1 4 47

38 Refractive index of glass is 1 5 Speed of light in vacuum is 3x10 m s The speed of light in the abovementioned glass is A 4x108 m s B 2 108 m s In the adjacent figure the tension in the string is 39 A 4 mg m B 2 mg T 3m C 4 5 108 m s LB 6 0 3 C mg D 3x108 m s 2 D mg

180 Mark for Review A parallel plate capacitor is charged and then battery is disconnected The effect of increasing the plate separation on charge potential and capacitance respectively is Constant constant increases Increases constant increases Increases increases decreases 02 59 Constant increases decreases

28 In the figure shown rod and block has same mass M The tension in the string connecting the rod to wall is 1 Mg 2 2Mg GCI 1 Mg 2 2Mg DTS Diamond Test Series for NEET 2021 G

A B 2 C U 3 D 4 E E The figure above shows four very thin parallel planes of charge with equal separation between them The charge density on plate 1 is 3 0 The charge density on plate 2 is 3 d The charge density on plate 3 is 10 The charge density on plate 4 is 1 0 Your answers for the electric field must include the correct sign We choose positive electric field along the positive x direction 53 in units of g

A human body has a surface area of approximately 1 m The normal body temperature is 10 K above the surrounding room temperature To Take the room temperature to be To 300 K For To 300 K and the value of a To 460 Wm where o is the Stefan Boltzmann constant Which 2017 of the following option is are correct A The amount of energy radiated by the body in 1 second is close to 60 Joules B If the surrounding temperature reduces by a small amount ATo To then to maintain the same body temperature the same living human being needs to radiate AW 40 T3 AT more energy per unit time C Reducing the exposed surface area of the body e g by curling up allows humans to maintain the same body temperature while reducing the energy lost by radiation D If the body temperature rises significantly then the peak in the spectrum of electromagnetic radiation emitted by the body would shift to longer wavelengths

2 8 9 10 11 12 13 14 15 16 1 Minute of attempt 40 138 What is the magnetic field at the centre of arc in the figure below I T 0 1 2 3 4 5 6 7 T From co i 2i A H 2 2 4 T r 2i BH 4 2 2 7 7 4 r To

Two charges of 10 C and 10 C are placed at points A and B separated by a distance of 10 cm What is electric field at a point Pon perpendicular bisector of AB at distance 12 cm from its mid point O 4 1 x 106 N C 2 1 x 104 N C 3 2 x 106 N C 4 5 x 107 N C

A charge q is moving in a circle of radius r with speed v Find magnetic field at centre of loop Hogv 4 r 1 3 Hogv 2r 2 qvr 2 qvr 4 4T

180 Mark for Review Mark the incorrect statement among the following A given conducting sphere cannot be charged to a potential greater than a certain value A given conducting sphere can be charged to a potential less than certain maximum value A given conducting sphere can be charged to any extent The metallic sphere may be negatively charged

A uniform ring of mass m and radius R can rotate freely about an axis passing through centre C and perpendicular to plane of paper Half of ring is positively charge and other half is negatively charge Uniform electric field Eg is switched on along ve axis Axis are shown in figure magnitude of charge density A Eo Co 2 C T If ring is slightly disturb from given position find the angular speed of ring when it rotate by 2 AEn 16AE TTA SXE TIL None L

Q16 A wooden block of mass 8 kg is tied to a string attached to the bottom of the tank In the equilibrium the block is completely immersed in water If relative density of wood is 0 8 and g 10 ms 2 the tension T in the string is a 120 N b 100 N c 80 N d 20 N

In meter bridge experiment null point is found at f 60 0 cm Value of 60 resistance is known to be accurate Value of R 3 is found to be 2 Find the value of n A R www Answer V 08 09 9 3 0 692 www B 1 02 03 04 05 06 07 00 01 02 03 04 05 06 07

34 180 Mark for Review Equipotential surfaces Are closer in regions of large electric fields compared to regions of lower electric fields Will be more crowded near sharp edges of a conductor Will always be equally spaced Both 1 and 2 are correct

4 First decreases then increases 12 12 Block A and B is connected with string as shown in the figure Coefficient of kinetic friction between block A of mass 4 kg and fixed inclined plane is If the block A is moving up the plane with constant speed then mass of block B is approximately 1 2 Kg 3 2 5 kg Akg 30 2 1 Kg 4 3 7 Kg 4 fegen k and yek a na na nez v g of a site faza ara afazita 1 2 Kg 3 2 5 Kg 4kg 30 2 1 Kg 4 3 7 Kg

A particle of mass m is projected with a velocity v kV k 1 from the surface of the earth Ve escape velocity The maximum height above the surface reached by the particle is 1 2 3 4 Rk 1 k R R k 1 k k 1 k R k 1 k 2 2 h R R t k 1 32 1 1 10 1 12 k 1

Sir in first option maximum atomisation to chromium ka hota ha then why iron is given Which of the following options does not correctly represent the correct order of the property indicated against it Fe Cr Mn Enthalpy of atomisation Cr Mn Fe Metallic radii Fe Mn Cr First ionisation enthalpy Mn Cr Fe Negative E M M Asked by 3592418 aesl id Standard XII Stream NEET Jul 27 2021 10 31 Add your responses Type Text

43 180 Mark Tor Review Two charges of 10 C and 10 C are placed at points A and B separated by a distance of 10 cm What is electric field at a point P on perpendicular bisector of AB at distance 12 cm from its mid point 4 1 106 N C 2 1 104 N C 3 2 106 N C hr min 4 5 107 N C

Two charges 8 C and 2 C are placed 10 cm apart The intensity of the electric field is zero at a point 1 10 cm from the first towards the second 2 10 cm from the first on the other side 3 5 cm from both the charges 4 20 cm from the first towards the second

Each minute earth receives about 2cal of heat energy per square centimeter form sun This is called solar constant S the value of solar constant in S l unit is A C D 8 kW m 2 1 4 kWm 1 8 kWm 2 2 5 kWm 2

Given the fermi energy and electron concentration 7 00 eV and 8 0x1026 e m respectively of a Copper of resistivity 1 7 108 2 m calculate the mean free path a 3780 nm b 5000 nm c 4100 nm d 7000 nm

A light is passing from air to a denser medium In the graph given above sin r is plotted against sin i where i and I are the angles of incidence and refraction respectively What will be the speed of light in the given medium Take the speed of light to be c in air 3 sin 37 sin r A C 5 37 sin i

Please read the question carefully and select the best choice The main source of sun s energy is OPTIONS Gravitational contraction Nuclear fusion Nuclear fission

12 A long straight wire along the Z axis carries a current i in the negetive Z direction The magnetic vector field B at a point having coordinate x y on the z 0 plane is A 0i xi yj 2n x 2 y 2 B 0i x yj 2 x 2 y 2 C 0i x yi 2 x 2 y 2 D 0 i yi x 2 x 2 y 2 1 point Clear selection 13 A long solenoid has 200 1 point

A 1 4 B 4 1 C 1 2 D 2 1 The ratio of r m s velocities the molecules of a gas kept at equal pressure and temperatures 800 K and 200 K respectively is A 4 1 B 2 1 C 1 2 D 1 4 50 A radioactive nucleus X undergoes a decay to form Y Y undergoes an a decay to form Z Under this transformation 49

An infinitely long hollow cylinder of radius a carrying R surface charge density a rotated about its cylindrical axis with a constant angular speed to Then find a The magnitude of vector potential at a distance R 2 from its axis

C 3 Two plano convex lenses each of focal length 10 cm refractive index are placed as shown in the figure In the space left water R I in air The optical power of the system is in dioptre is filled The whole arrangement is

Consider the following statements Which statements are wrong Two large conducting spheres carrying charges Q and Q are brought close to each other then the magnitude of electrostatic force vs Q Q 4 or r is the distance between their centres between them will be exactly 1 2 If Coulomb s law involves 3 dependence 2 where instead of 1 the Gauss s law will still be 2 true 3 A small test charge is released at rest at a point in an electrostatic field configuration then it will necessarily travel along the line of force passing through that point 4 The electric field is discontinues where as electric potential is continuous across the

Q 5 In the given figure a ball of mass m is connected to an elastic spring of mg force constant K through an L inextensible string as shown Now the ball is released from rest a b C d K mg L vooooo m 1 2 The maximum velocity of mass m during fall is 2gL The maximum velocity of mass m during fall is 3gL The maximum potential energy stored in the spring during the fall is mgl 3 2 The maximum potential energy stored in the spring during the fall mal 61

From a circular ring of mass M and radius R an arc corresponding to a 90 sector is removed The moment of inertia of the remaining part of the ring about an axis passing through the centre of the ring and perpendicular to the plane of the ring is K times MR2 Then the value of K is 1 2 3 1 100

A thief in a car moving with uniform speed passes a stationary policeman who is hiding behind a wall with a motorcycle After 2 0 s delay reaction time the policeman accelerates to his maximum speed 150 km hr in 12 sec and catches the thief at 1 5 km beyond the wall The speed of thief is 17 50 m s 34 10 m s 51 20 m s 25 20 m la

21 AB is a vertical rigid infinite wire carrying a linear charge of density 2 10 C m A particle having mass m 2 g and charge Q 1 C is fixed to the wire by means of a light insulating and inextensible string having length 2 2 m The vertical velocity u in with which it should be projected under gravity from the shown position so that the string slacks when its angle with vertical becomes 45 is correct upto the first two decimal places U m l A a

Two capacitors are fully charged as shown in the figure Then cell is taken out and the two capacitors are connected together such that plates of opposite polarity are connected together Choose the correct statements C HH E 2C 1 Charge on capacitor of capacitance Cis 4CE 9 OMA Charge on capacitor of capacitance 20 is 8CE 9 3 Charge on capacitor of capacitance 2C is zero 4 Energy loss in the process of charge

A stretched string fixed at both ends vibrates at frequency of 12 Hz with standing wave pattern as shown in figure Select the correct alternative 1 The fundamental frequency is 6 Hz 2 The fundamental frequency is 4 Hz 3 The frequency of first overtone is 8 Hz 4 The frequency of first overtone is 6 Hz

An ideal gas is expanded so that the amount of heat given is equal to the decrease in internal energy of the gas The gas undergoes the process oll PVs constant The gas may be B D He 0 Ar All of these

An electric dipole of length 1 cm is placed with its axis making an angle of 30 to electric field direction of electric field strength of 104 N C If it experiences a torque of 10 2 Nm the magnitude of potential energy of the dipole is 12 6 J 24 5 J 18 75 J 20 C

Starting from rest a particle is first accelerated for time with constant acceleration a and then stops in time t with constant retardation b Let v be the average velocity in this case and S be the total displacement In second case it is accelerated for same time with constant acceleration 2a and come to rest with constant retardation 3b in time t3 If v2 is average velocity in this case and S is the total displacement then V2 2V 2V V1 2S S S 3 S S 2S

Single Correct A body is heated to a temperature 40 C and kept in a chamber maintained at 20 C If the temperature of the body decreases to 36 C in 2 minute then the time after which the temperature will further decrease by 4 C is 2 minutes 2 minutes 33 seconds 2 minutes 55 seconds 3 minutes Marks 4 00 1

An ideal Carnot engine whose efficiency is 40 receives heat at 500 K If its efficiency is 50 then the intake temperature for the same exhaust temperature is a 800 K c 600 K b 900 K d 700 K 1995