Basic Physics Questions and Answers

39 A uniform rope of length L and mass m hang vertically from a rigid support A block of mas m is attached to the free end of the rope transverse pulse of wavelength 2 is produced the lower end of the rope The wavelength of th pulse when it reaches the top of the rope is 2 T ratio 2 2 is 1 3 m m m2 m 2 4 m m m m m m

3 FL0002 For steel the breaking stress is 6 x 10 N m and the 8 density is 8x10 kg m The maximum length of steel wire which can be suspended without breaking under its own weight is g 10 m s 1 140 m 3 75 m 2 120 m i 200m Session 4

Nitrobenzene on reaction with conc H NO3 H2SO4 at 80 100 C forms which one of the following products 2013 NEET O examsnet com O 1 4 Dinitrobenzene O 1 2 4 Trinitrobenzene O 1 2 Dinitrobenzene O1 3 Dinitrobenzene

29 Figure shows two cases In first case a spring spring constant K is pulled by two equal and opposite forces F at both ends and in second case is pulled by a force Fat one end Extensions x in the springs will be Fm F mm F 1 In both cases 2 In both cases x 3 In first case x 2F K F K 2F K in second case x F K 33

The Fourier transform F k of a function f x is defined as F k 1 8 f x exp x is Given exp x dx x a xp k b exp k 4 T exp k 2 88 dx f x exp ikx The F k for d 2 exp k

A periodic function f x x for 1 x has the Fourier series representation x 2 7 1 n 1 a 2 In 2 1 sin nx Using this one finds the sum b w th 1 c TC 8 n n l 2 to be d In 2

Over a smooth light pulley is passed a string supporting at one end a weight of mass 4 kg At the other end of the string is a pulley of mass 1 kg Two masses of 2 kg and 3 kg are suspended on either side of the 1kg pulley as shown in figure The acceleration of the 4 kg mass is ng 49 Find n 1kg 4kg

3 Two inductor coils L 18 mH and L 8 mH are perfectly coupled If a current of 2 A is reversed in first coil within 2 millisecond then the EMF induced in the second coil will be 1 12 volt 3 12 mV 2 24 volt 4 24 mV

5 A particle of mass m moves with constant speed v on a circular path of radius r as shown in figure The average force on it during its motion from A to B is 1 3 3mv 2 r 2 3mv Tur 2 E mv 3 3mv Anr

Following limiting molar conductivities are given as A H SO4 x S cm mol 1 Am K SO4 y S cm mol Am CH3COOK z S cm mol in S cm mol for CH3COOH will be 1 x y 2 3 x y z Z NEET 2019 Odisha 2 x y 2z 4 xy 7

A weight W is tied to two strings passing over the frictionless pulleys A and B as shown in the figure If weights P and Q move downwards with speed V the weight W at any instant rises with the speed 1 V cose 3 V cos 2 2V cose 4 2V cos0 poiling of a room With how much

A car running at 30 km hr stops after travelling 8m distance on applying brakes If same type of is running at 60 km hr it stops after travelling how much distance on applying brakes 1 8 metres 2 16 metres 4 32 metres 3 24 metres Two masses 10k

ideal gas undergoes the process A B in the given p V diagram The molar heat capacity for this process is 3R 13R b 6 d 2R a c 2 5R 2 6PO 3Po A B Vo 5V

3 If a particle is moving on a circular path with constant speed then the angle between the direction of accelera and its position vector w r t centre of circle will be 1 Zero N

Two masses 10 kg and 20 kg are connected with a massless spring as shown in the figure A force of 200 N is acting on the mass 20 kg When the acceleration of 10 kg mass is 12m s the acceleration of 20 kg mass is 1 12 m sec 2 4 m sec 3 10 m sec 4 zero Three block are copper 1000000 20kg

3 Two blocks of mass m m connected with a light spring placed on a frictionless table They are left after pulling with same force then the ratio of acceleration produced in them m1 1 m2 3 m m2 m m2 2 m2 m 4m m2 4 m m

1 What will be the focal length of a lens having power 2 5 m Is the lens converging or diverging 40 cm converging ii Calculate the power of a convex lens having focal length 20 cm 5 m 1

4 60 N In the following figure two blocks on m 2kg and m 1kg are in contact with a frictionless table A horizontal force F 3N is applied to mass m the contact force between m and m will be 1 1N 2 2N 3 3N 4 zero Two blocks are connect m 2kg 1kg m 1

2 1 biconvex lens of radius of curvature R is made up of a variable refractive index 2 incipal axis as shown in figure The spread of image lies over a span of d X Assume 2d R A point object is placed at R70m on

onvex lens of radius of curvature R is made up of a variable refractive index 21 1 1 Assume 2d R A point object is placed at R 7 5 m on the principal axis as shown in figure The spread of image lies over a span of y O d d X

A capacitor of capacitance 2uF is charged to a potential difference of 200 V After disconnecting from the battery it is connected in parallel with an another unchanged capacitor The common potential is 20 V The capacitance of the second capacitor is 1 2 F 2 F 2 4uF 3 18 F 4 16 F

Sir please give diagram for each part and show both horiz ontal components of earth magnetic field and earth field a nd conductor please give precise diagram Illustration 32 The horizontal component of the earth s magnetic field at a certain place is 3 x 10 5 T and the direction of the field is from the geographic south to the geographic north A very long straight conductor is carrying a steady current of 1 A What is the force per unit length on it when it is placed on a horizontal table and the direction of the current is a east to west b south to north FCURRENT MAGNETISMO1 THEORY P65

4 It may be non inertial frame of reference As shown in the figure two masses is 15 kg each are suspended through two strings tied to a spring balance after passing over frictionless pulleys The reading of the balance will be 1 zero 3 30 kg 2 15 kg 4 7 5 kg longth 30 cm is shown String shown 15kg A KALAY 10cm 20cm 15k

3 V cos 4 2V cos0 A body of weight W is suspended by a chain of weight W from ceiling of a room With how much force ceiling pulls the chain 1 W 2 W 3 W W 4 W W 2 A person says that he measured acceleration of a particle non zero while any force is not acting

Three blocks A B and C of mass m and m of different densities and dimensions are placed over each other as shown in the figure The coefficients of friction are 2 shown Blocks placed in a vertical line are made to move towards right with same velocity at the same instant Find the time in sec taken by the upper block A to topple from the middle block B Assume that slipping at any surface don t stop before A topples from B w 4 2L 1 2 B L w 2

An elastic spring has length x when it has tension of 4 N and length y when tension is 5 N The tension in the spring when its length is 5y 4x will be 1 7 N 3 11 N 2 9 N 4 15 N

Consider the following statement s a Most accurate reading must be most precise too b Less accurate reading may be more precise Choose the correct statements O a only Ob only O Both a and b ONeither a nor b

An aeroplane takes the photograph of the earth s surface from a height of 1000 m from the surface of the earth with the help of a camera If the focal length of lens of the cam era is 50 cm what is the magnification of the image 0 0005

EXAMPLE 4 Position Vector The position of a particle is given by ection r 3 0 t i 2 0 t j 5 0 k 2 where t is in seconds and the coefficients have the proper units for r to be in metres i Find v t and a t of the particles ii Find the magnitude and direction of

The focal length of lens of a camera is 12 cm With the help of this camera a distant object is focussed Now to focus another object at a distance of 1 m away from the first object through what distance must the lens of the camera be moved 1 636 cm

An object is placed at a distance of x cm from a concave mirror and its real image is received on a screen placed at a distance of y cm from the mirror The focal length of the mirror is z cm The values of x are changed and the coresponding values of y are measured Which one of the graphs shown in figure represents the best variation of y with x y y O y AX y 1 C AX X AX

A body is projected at an angle of 60 with the horizontal If its kinetic energy at its maximum height is 10 J then the height at which its potential energy nd kinetic energy have equal values is consider potential energy at the point of projection to be zero A B half of the maximum height two third of the maximum height Correct Answer Your Answer one sixth of the maximum height

vi A series circuit consists of a resistance inductance and capacitance The applied voltage and the current at any instant are given as e 141 4 cos 300t 10 and i 5 cos 3000t 55 The inductance is 0 01H Calculate the values of the resistance and capacitance

viii In the middle of a long solenoid there is a coaxial ring of square cross section made of conducting material with resistivity p The thickness of the ring is equal to h its inside and outside radii are equal to a and b respectively Find the current induced in the ring if the magnetic induction produced by the solenoid varies with time as B Bt where is a constant h b a 4p

Consider the following statements a 0 020430 has two significant zeros b 0 475 is equal to 0 48 in two significant figures Choose the incorrect statement s a only b only O Both a and b Neither a nor b

A biconvex lens of radius of curvature R is made up of a variable refractive index 2 2 1 7 principal axis as shown in figure The spread of image lies over a span of Assume 2d R A point object is placed at R 7 5 m on the

The least count of a stopwatch is 0 01 s The time of 20 oscillations of a pendulum is measured to be 40 00 seconds The maximum percentage error in the measurement of time will be O 2 5 O 4 O 0 25 O 0 025

Which among the following is dimensionally incorrect Here h Height T Surface tension p Density P Pressure V Volume n Coefficient of viscosity V Frequency Moment of inertia g Acceleration due to gravity R Radius t Time m Mass Length v Speed 0 h 2T cose pRg Ov P P R4

A particle is moving with uniform acceleration Its position x is given in terms of time tin s as x 5t 4t 8 m then O Its initial velocity is 8 m s O Its velocity at time t 3 s is 36 m s O Its acceleration is 5 m s Its position at t 2 s is 36 m

A cyclotron s oscillatory frequency is MHz What should be the operatin magnetic field for accelerating deuterons NCERT Pg 14 1 0 96 T 3 0 46 T 2 1 52 T

Consider a tightly wound 100 turn coil o radius 12 cm carrying current of 10 A What is magnetic field at centre of this coil NCERT Pg 146 1 1 2 x 10 T 2 5 2 x 10 T 3 4 6 x 10 5T 4 1 9 x 10 T

v Calculate the root mean square value of the voltage o the given variation of an alternating EMF with time in graph a shown in figure 5 173 Vo T 2 T 3T 2 2T Figure 5 173

A 200 V ac supply is connected between A and B as shown in the figure The final potential difference across the capacitor will be if 2 200 V ac 200 V 100 V 55 19 100 2 V

A class XI student Suresh performs an experiment to measure the volume of a room Interior He measures the inner dimensions as 3 0 m 4 00 m and 5 00 m The volume of the room with correct significant figure is 60 00 m O 6 00 10 m O 6 0 10 m O 60 m

vii The potential difference across a 150mH inductor as a function of time is shown in figure 5 119 Assume that the initial value of the current in the inductor is zero What is the current when a t 2 0ms b t 4 0ms V volt 5 0 4 0 3 0 2 0 1 0 0 1 0 2 0 3 0 Figure 5 119 a 3 33 x 10 2 A b 6 67 x 10 A 4 0 ms

3L A uniform chain of length L has one of its end attached to a vertical wall at point A while of the length of the chain is lying on table as shown in figure Tangent to 4 chain at A makes an angle 37 with the wall Find the minimum coefficient of friction between table and chain so that chain remains in equilibrium A Felllllllllllll 37 0000000000

Find the inductance of a unit length of a double line if the radius of each wire is n times less than the distance between the axes of the wires The field inside the wires is to be neglected the permeability is assumed to be equal to unity throughout and n 1 PeIn n TC

There is a parallelopipe formed by three non co planer vector a b and c Then a a volume of the parallelo pipe is given by a 6x b Diagonal of the parallelopipe is given by a b c B only a is ture only b is true both a and b are true

In a common emitter amplifier the audio signal voltage across the collector of resistance 3 ko is 3 V The current gain is 80 and base resistance is 1 k The power gain of the amplifier is O 19200 O 6400 O 240 O 720

A ring of mass m 1 2 kg can slide over a smooth vertical rod A light string attached to the ring is passing over a smooth fixed pulley at a distance of L 0 5 m from the rod as shown in the figure At the other end of the string mass M 3 kg is attached lying over a smooth fixed inclined plane of inclination angle 37 The ring is held in level with the pulley and released Determine the velocity of the ring when the string makes an angle a 37 with horizontal 1 4 m s 0 84 m s 0 6 m s 01 m s 37 Save Ne