Basic Physics Questions and Answers

The balancing potentiometer length for a cell is 560 cm in a experiment When an external resistance of 10 is connected in parallel to cell the balancing length change by 60 cm The internal resistance of cell in ohm is 1 6 1 4 1 2 1 0

8 a Name the type of radiation which when enters the muscle tissues produces heat b Name the type of radiation that is used in communication using cellphones c Which among the following radiation has a lower frequency Violet light Red light

iv Deduce the moment of inertia for a hollow spherical shell about an axis passing through its centre Also deduce the moment of inertia of the same shell if the axis of rotation is passing through one of its tangents 6 4 10

A Non inverting Op Amp has input resitance of 6 6 K Ohm and feed back resistance of 68 K Ohm If the input voltage is 0 7 What is the output voltage of Op Amp 101924461 NOTELO

6 Select the correct relation between speed of sound in a and elasticity of air 1 Speedo adiabatic elasticity of air 2 Speed adiabatic elasticity of air 3 Speed isothermal elasticity of air 4 Speed isothermal elasticity of air X x

For a series R L C Network is shown determine the un damped natural frequency and damping ratio of the circuit 6v S 10 5 rad sec 0 25 10 5 rad sec 0 5 10 4 rad sec 0 5 10 4 rad sec 0 25 1kQ 10mH 0 01

94 A particle started revolving from rest with a constant angular acceleration a in a circular path of radius r If centripetal acceleration becomes numerically equal to tangential acceleration at time t then t is equal to POW 1 t 3 1 a 1 fhow 1 2 t 2250 5 a tese TE 2 0 C 4 t 010 4

229 If A and B are two vectors inclined to each other at angle 0 then component of A perpendicular to B and lying in the plane containing A and B is A S A B A B low 61 tete1 ts prin Berit no vising 2 A Bsmi Bioge narw Jis B teg erit to Toge en ap to elons 4 A B 901002 nge prinio prit ofT allow orl diw 3 A R

a State and prove Gauss theorem of electrostatics Using this find the electric field near a uniformly charged plane sheet b If the intensity of the electric field near the earth s surface is 330 V m directed downwards calculate the surface density of charge on the earth s surface

the figure a 5cm and b 20cm If the M I of th wheel is 3200kg m the angular acceleration would be 12X1 6 0 1 10 1 rad s 3 10 3 rad s 12 N 30 10N 9N LFL s d 2 10 rad s 4 10 4 rad s d

In the arrangement shown in figure the mass of the rod M exceeds the mass m of the ball The ball has an opening permitting it to slide along the thread with some friction The mass of the pulley and the friction in its axle are negligible At the initial moment the ball was located opposite the lower end of the rod When set free both bodies began moving with constant accelerations Find the friction force between the ball and the thread if t seconds after the beginning of motion the ball got opposite the upper end of the rod The rod length equals l I

27 Three bulbs of 40 W 60 W and 100 W are arranged in series with 220 V Which bulb has minimum resistance 1 100 W 3 60 W 2 40 W 4 Equal in all bulbs Hint Resistance doesn t depend on external voltage or series parallel connection Larger the power lower the resistance

assumed to be perfectly conducting 30 69 E A wwww 62 www B 302 TEU 7 Statement 1 The current in branch AB is non zero Statement 2 The potential difference between A and B is non zero Choose the correct option 1 Statement 1 is correct but Statement 2 incorrect 2 Statement 2 is correct but Statement 1 incorrect 3 Both statement are correct

A person cannot see objects distinctly at a distance less than 1 m The power of the spectacles that he use in order to read a paper at a distance of 0 25 m is O 4D O 0 5 D O 3D O 3D

Transfer function of following system is R s G G G1 G2 1 G1G3 G1G4 G2G3 G2G4 G G1G2 G3G4 1 G1G3 G1G4 G2G3 G2G4 G1 G2 1 G1G3 G1G4 G2G3 G2G4 GA G1 G2 G3 G4 1 G1G3 G1G4 G2G3 G2G4 C s

38 It is raining at 20 m s in still air Now a wind starts blowing with speed 10 m s in north direction If a cyclist starts moving at 10 m s in south direction then the apparent velocity of rain with respect to cyclist is sqa rtw balosing balosiong al altbetong A Ter 1 20 m s 2 20 2 m s 19306 nee 3 10 5 m seshorer 4 30 m semits

When a projectile is fired at an angle 8 w r t horizontal with velocity u then its vertical component till body reaches its maximum height Remains same Goes on increasing with height Goes on decreasing with height First increases then decreases with height

10 Figure shows graph between and V for two conductors A and B Their respective resistances are in the ratio A V Z JK V R 1 1 1 3 3 1 30 30 A B V V 2 1 3 4 1 2 ton 30 160 1 5

A plane boundary separates two transparent media A and B The speed of light in medium A is 1 5 x 108 m s and in medium B is 2 0 x 108 ms The critical angle for which ray of light going from A to B gets totally internally reflected is O sin sin O sin O sin 1

24 The instant at which a bulb is switched on its power is maximum then it decreases to a steady value Explain

4 A ball of mass m moving with a speed u undergoes a head on elastic collision with a ball of mass nm initially at rest The fraction of the incident energy transferred to the heavier ball is 1 n 1 n 2n 3 1 n 2 n 1 n 4n 4 1 n

One mole of an ideal gas expands from initial state 27 Vo to final state To 2V The process of expansion Work done by the gas TOV 3T is given by T during the expansion is 7 temperature V volume 1 RT In2 2 3RT In2 3 RT 31n2 1 4 To Vo 0

A charge of 10 C flows from point A to B Work done on charge is 8 x 10 3 J What is the potential of point A if potential of point B is VB 1000 volt 50 V O 150 V O 100 V O 200 V

which of the following statement is correct P The addition of pole to an OLTF pulls the root locus to the right Q The addition of pole to an OLTF pulls the root locus to the Left R The addition of zero to an OLTF pulls the root locus to the right S The addition of zero to an OLTF pulls the root locus to the Left P S Q R PR

A force F is applied to a dumbbell kept on smooth surface 1 for a time interval t first as in figure i and then as in figure ii The final speed of centre of mass in figure i is v and figure ii is V V2 then E i Y 2x0 3 1 5X10 F m UFULI 1 1 nx 1 889 1 V V 2 v v 3 4 Depends on the rotational inertia of the dumbbell 1 SX onal 99 1

Hint P VI 29 Three equal resistors connected in series across a source of EMF together dissipate 10 W of power What would be the power dissipated if the same resistors are connected in parallel across the same source of EMF 1 25 W 3 45 W Hint P parallel n n 3 Pe series 2 80 W 4 90 W

Some of the statements regarding ethanol and ethanoic acid are given below i Ethanoic acid has a pungent smell while ethanol has a pleasant smell ii Ethanoic acid gives litmus test but ethanol does not give litmus test iii The boiling point of ethanoic acid is higher than that of ethanol iv Ethanol can react with NaOH but ethanoic acid doesn t Which statement is correct O i and iv only Oii and iv only Oi ii iii only Oi ii iii and iv

5 A tank containing water of mass M is placed on a weighing machine A stone of weight w is hung and lowered in water without touching the sides If volume of stone is V and density of water is p what will be the reading of weighing machine in kgf now 1 M pV M 11 2 M ng ev M US mangford

91 A projectile is projected from ground with veloci 0 V at an angle 0 with horizontal What is th vertical component of velocity of projectile when vertical displacement is equal to half of th maximum height attained 0 1 3vo cose 2 sin 2 0 COSA duaibheque 01638 A 0 mont noto 26 ellos

ving 76 Which of the foll 1 Two physical quantities having the same dimension can always be added 2 Precision always leads to accuracy 3 A dimensionally correct equation is always correct 4 If z A Bb then AA AB a b AZ Z may not be equal to

A small ball of mass 1 kg moves inside a smooth fixed cylinder of radius 1 m in vertical plane Axis of cylinder is horizontal The acceleration of the ball at point B is Given that velocity of ball at point A is 5 m s and g 10 m s mx 2 5 m s 3 15 m s O B ou mg 2 25 m s 4 5 5 m s S 0 NXES 25 20

Indicate the false statement You can select multiple options Modulation is the process of putting information onto a high frequency carrier The transmitter block in communications system contains the demodulator device The receiver block in any communications system contains the modulator device Modulation is the process of preserving all the properties of carrier signal

A small mirror used by a dentist gives a magnification of 5 when it is held at a distance of 0 50 cm from a toot The radius of curvature and nature of the mirror used is O 1 25 cm convex 1 60 cm convex O 1 60 cm concave 1 25 cm concave

Two projectiles of same mass and same initial speed are thrown at 60 and 30 with vertical then which will remain constant Time of flight Horizontal range Maximum height reached min s Maximum height and range

32 Which component is related to generation of nerve impulse resulting in sensation of hearing 1 Vibration of ear drum due to sound waves 2 Entry of vibrations in perilymph via circular window Generation of vibrations in reissner membrane

Consider the situation shown in the figure The capa A has a charge q on it whereas B is uncharged The charge appearing on the capacitor B a long time after the switch is closed is Zero H Bedfo www A 2 q 2 B F

8 It is a method that is conducted in laboratories wherein the sample or specimen is being evaluated a census b experimentation c interview d observation 3 It refers to the whole set of individuals objects measurements and happenings a census b population c sample d statistics

1 A cylinder of length 10 cm made of material of density 0 65 g cm floats half submerged in an ideal liquid kept in closed vessel as shown in the figure Air in the vessel has density 1 30 kg m If pressure of air in the vessel in made 100 times of its initial value what will you observe a The cylinder moves upwards b The cylinder moves downwards c Displacement of the cylinder is 0 56 cm d Displacement of the cylinder is 0 60 cm

If equation for angular displacement of a particle moving on circular path is given by e 2t 6 where 0 is in radian and t in second then angular velocity of the particle at t 2 seconds is 6 rad s 1 8 rad s 1 12 rad s 1 24 rad s 1

Which statement is not true 1 Nerve impulse include wave of depolarisation 2 Nerve impulse include wave of repolarisation 3 Synaptic cleft is a gap which is always presen between presynaptic post synaptic neurons

60 If a particle moves in a circle describing equal angle in equal time then its velocity vector Remains constant Changes in magnitude Changes in direction Changes in magnitude and direction min

Which of the following operations is not possible in case of scalars and vectors

In a new system of units unit of mass is 10 kg un length is 1 km and unit of time is 1 minute the value of joule in this new hypothetical system is 1 3 6 104 new units 2 6 107 new units 3 10 1 new units 4 1 67 104 new units

A conducting circular loop is placed in a uniform magnetic field of induction B tesla with its plane normal to the field Now the radius of the loop starts shrinking at the rate dr dt r wil Then the induced emf at the instant when the radius is be rB 2 rB 2 Tr dr dt 2 2 dr dt dB dt B dr dt

1 Two particles are in SHM on same straight line with amplitude A and 2A and with same angular frequency It is observed that when first particle is at a dis tance A 2 from origin and going toward mean po sition other particle is at extreme position on other side of mean position Find phase difference between the two particles 45 2 90 3 135 4 180

The capacitors are initially uncharged In a certain time the capacitor of capacitance 2uF gets a charge 20 C In that time interval the heat produced in the three riesistoris 2 3 and 6 is H H and H respectively then H H3 H in J is 20 wwww T20V 30 60 1 F 2uF

A 0 5A B 0 707A C 1 414A D 1 A A p d of 100V is applied across a copper wire of length 1m The average drif velocity of electron is Take n 8 5x10 m a 5 81 x 107 22 m A 4 3x 10 mvs B 43x10 mvs C 0 43 m s D 0 036 m s

19 The angle of dip is 0 on a given meridian which at an angle 0 with the magnetic meridian If 8 i perpendicular to the first meridian then 8 8 am the angle of dip on another meridian which 02 are related as 1 cot 0 cot 0 cot 0 2 tan 0 tan 0 tan 0 3 tane tan 0 tan 02 1 tanf tong tan A tane

A hollow spherical shell is compressed to half its radius The gravitational potential at the centre 1 increases 2 decreases 3 remains same 4 during the compression increases then returns at the previous value

A body is just floating in a liquid their densities are equal If the body is slightly pressed down and re leased it will 1 start oscillating 2 sink to the bottom 3 come back to the same position immediately come back to the same position slowly