Experiments Questions and Answers

In a potentiometer experiment the balance length is 8m when the two cells E and E are joined in series When the two cells are connected in opposition the balance length is 4 m The ratio of the emf of two cells E E is a 1 2 c 1 4 b 2 1 d 3 1

Q11 A manometer reads the pressure of a gas in an enclosure as shown in the figure The absolute and gauge pressure of the gas in cm of mercury is Mercury Take atmospheric pressure 76 cm of mercury a 76 20 b 20 76 c 96 20 d 20 96 Mercury 20 cm

20 An a c signal is fed to two circuits X and Y and the corresponding outputs in the two cases have the waveforms shown below Name the circuits X and Y and also give the minimum number of semiconductor diodes used in each of these circuits wohn Momm n

5 A student measured the diameter of a small steel ball using a screw gauge of least count 0 001 cm The main scale reading is 5 mm and zero of circular scale division coincides with 25 divisions above the reference level If screw gauge has a zero error of 0 004 cm the correct diameter of the ball is a 0 521 cm c 0 053 cm b 0 525 cm d 0 529 cm

When a cube is placed between the jaws of a vernier calipers 0 mark on Vernier is to the right of 2 5cm mark and 7th mark on Vernier coincides with a mark on main scale If there no zero error find the edge length of the cube One main scale division is 1mm and 10 vernier scale divisions coincide with 9 divisions on main scale find the edge length of cube 1 2 57cm 2 3 57cm 3 1 57cm 4 4 57cm

2 For the system free particle determine x and p The quantum mechanical average of a series of measurements the expectation value is given by O all space dv Sall space 4 dv Show that x 0 a to a limit of integration p 2mE 2 0 to 1 limit of integration

The given figure shows the two scales of a screw gauge The pitch of screw is 5 mm and the total number of divisions on the circular scale is 50 Find a The type of error b If this screw gauge is used to measure an object and the observed reading of the objec is 10 5 cm what will be the correct reading Base line

Light of wavelength 650 nm and power 2 mW is incident on a semiconductor photodiode with an absorbing layer of thickness 2 65 m Assume that 1 of power is lost on reflection at the surface and the absorption coefficient at this wavelength is 10 cm What will be the absorbed power

n meter bridge experiment null point is found ate 60 0 cm Value of 60 resistance is known to be accurate Value of Ris found to be on Find the value of n 60 www www Answer 01 00 03

l In meter bridge experiment null point is found at 60 0 cm Value of 6 Q resistance is known to be 3 accurate Value of Ris found to be 9 e s 2 Find n the value of n R www A 622 www hr min B Answer 0 01 02 03 03 04 05 06 07 08 09

The length of a potentiometer wire is 1200 cm and it carries a current of 60 mA For a cell of emf 5V and internal resistance of 2002 the null point on it is found to be a 1000cm The resistance of whole wire is 1 12092 2 6092 3 802 1000

A uniform square plate and a disc have same mass per unit area are kept in contact as shown in figure Diameter of disc is equal to side length of square The position of centre of mass is At distance At distance At distance from centre of square on line joining centre of objects 4 R from centre of square on line joining centre of objects At mid point from centre of square with the disc 4 a from centre of square on line joining centre of objects

A screw gauge with a pitch of 0 5 mm and a circular scale with 50 divisions is used to measure the thickness of a thin sheet of aluminum Before starting the measurement it is found that when the two jaws of the screw gauge are brought in contact the th 45 division coincides with the main scale line and that the zero of the main scale is barely visible What is the thickness of the sheet if the main scale reading is 0 5mm and the 25 th division coincides with the main scale line O O 0 75 mm 0 80 mm 0 70 mm 0 50 mm

A potentiometer wire of length 1 m has a resistance of 10 ohm It is connected in series with a resistance R and a cell of emf 3 V and negligible internal resistance A source of emf 10 mV is balanced against a length of 60 m of the potentiometer wire Find the volue of R

Six students measure the resistance of a lamp Their answers in 2 are 410 667 439 641 684 and 928 Find the mean value mean absolute error the relative error and the percentage error in the measurement of lamp

start 31 A man is 45 m behind the bus when the bus accelerating from rest with acceleration 2 5 ms 2 With what minimum velocity should the man star running to catch the bus a 12 ms b 14 ms d 16 ms A hodu c 15 ms

A screw gauge with pitch 1 mm and 100 divisions on circular scale is used to measure the thickness of a glass slab When there is no object between the studs and the faces of the screw gauge touch each other the 40th division of circular scale coincides with the reference line Now the glass place is held between the studs and reading of linear scale is found to be 5 and that of circular scale is 26 What is the thickness the glass plate It is given that zero of linear scale is not visible when the faces touch each other

A constant respectively When the pressure reading is 1 25 C 3 15 C 2 40 C 4 12 5 C On centigrade scale the temperature of a body increases by 30 degrees The increase in temperature om Fahrenheit scale is 1 50 3 30 2 40 4 54 10 cm at 20 C At 19 C it will be a 11 x 10 6 C 10 6 cm shorter

are given that L EE VED MSD Why Least count of er ier caliper L C xVD 1x M where V S D is the Vernier Scale Divison and M S D is the Main Scale Division Given 5 V S D 3 M S D and 1 V S D 0 6 mm L C 2 x V S D 1 x M S D 2 x 0 6 5 3 0 6

The sum of two forces acting force is 8 W and its direction then the forces are a 6 N and 10 N c 4 N and 12 N at a point is 16 A If the resultan is perpendicular to minimum forc CPMT 1997 8 N and 8 N 2 N and 14 N b d

3 speed may increase 4 With positive value of acceleration speed must increase A drunkard walking in a narrow lane takes 5 h steps forward 3 steps backward and then ON stay for 1 s and repeat the same process again and again Each step is 1 m long and takes 1 s The time taken by drunkard to fall in a pit 10 m away from start is NCERT Pg 56 1 45 s 3 30 s 2 27 s 4 31 s In any realistic condition v t graph cannot have sharp kink points This implies that NO 1 Both velocity and accel change abruptly at an insta 2 Both velocity and acceler change abruptly at an insta 3 Only velocity cannot chan an instant but acceleration 4 Orly acceleration ca abruptly at an instant b change

In the arrangement shown in the figure A is an equilateral wedge and the ball B is rolling down the incline XO Find the velocity of the wedge of course along OY at the moment velocity of the ball is 10 m s parallel to the incline XO 60 B 10 m s 30

Q45 In a Young s double slit experiment the upper slit is covered by a thin glass plate of refractive index 1 4 while the lower slit is covered by another glass plate having the same thickness as the first one but having refractive index 1 7 Interference pattern is observed using light of wavelength 5400 It is found that the point P on the screen where the central maximum n 0 falls before the glass plates were inserted now has 3 4 the original intensity It is further observed that what used to be the fifth maximum earlier lies below the point P while the sixth minima lies above P Calculate the thickness of glass plate Absorption of light by glass plate may be neglected 1997

5 180 A student measures the period of oscillation of a simple pendulum in successive measurements the reading turn out to be 1 98 s 1 99 s 2 06 s 2 08 s and 1 95 s A more accurate way to write the measurement with error is 2 0 0 1 s 2 03 0 06 s X 2 0 0 06 s O2 03 0 1 s

In the double slit experiment what should be the width of each slit to obtain 8 maxima of the double slit pattern within the central maxima of single slit pattern with d 3 mm O 0 6 mm O 0 4 mm O 0 75 mm 0 3 mm

The Binding energy per nucleon of Li and He nuclei are 5 60 MeV and 7 06 MeV respectively In the nuclear reaction Li H He Q the value of energy Q released is 1 19 6 MeV 201 3 8 4 MeV 2 2 4 MeV 08 4 17 3 MeV 616 109 yea

The position time graph for two particles is given s m 30 20 to lo 20 A t s of velocity and directio a What is the magnitude of motion of A b What is the separation between A and B

2 A cylindrical tube L 120 cm is resonant with a tuning fork of frequency 330 Hz If it is filling by water then to get resonance minimum length of water column is Vair 330 m s neglect end correction 45 cm 3 25 cm X2 60 cm 4 20 cm

7 A student measured the diameter of a small steel ball using a screw gauge of least count 0 001 cm The main scale reading is 5 mm and zero of circular scale division coincides with 25 divisions above the reference level If screw gauge has a zero error of 0 004 cm the correct diameter of the ball is 1 0 521 cm 3 0 053 cm 2 0 525 cm 4 0 529 cm

A boy uses a thread of length 6 300 01mm to measure the circumference of a sphere He measures the diameter using a screw gauge with 2 main scale division visible and 0th circular scale division coincides with main scale What is the value of that the student reports 1 main scale division 1mm there are 100 divisions on circular scale 03 15 0 02 03 15 0 05 3 15 0 04 3 15 0 01 O

A particle moves along X axis in such a way that its x coordinate varies with time t according to the equation x 6 4t 6t2 metre The velocity of the particle will vary with time according to the graph V v 5 A C B D

The main scale of vernier calipers reads in millimeter and its one division is equal to 1 mm Its vernier is divided into 16 division which coincide with 15 division of main scale Further more when a rod is tightly placed along its length between two jaws it is observed that the zero vernier scale lies just right to 32 division of main scale and 4th division of vernier scale coincide with main scale What is the length of rod in mm

Q 24 During Searle s experiment zero of the Vernier scale lies between 3 20 x 10 2 m and 3 25 x 10 2 m of the main scale The 20th division of the Vernier scale exactly coincides with one of the main scale divisions When an additional load of 2 kg is applied to the wire the zero of the Vernier scale still lies between 3 20 x 10 2 m and 3 25 x 10 2 m of the main scale but now 45th division of Vernier scale coincides with one of the main scale divisions The length of the thin metallic wire is 2 m and its cross sectional area is 8 x 10 7 m The least count of the Vernier scale is 1 0 x 10 5 m The maximum percentage error in the Young s modu of the wir la 001

Which one of the following statement is false Question Type Single Correct Type 1 Pure Si doped with trivalent 2 impurities gives a p type semiconductor 3 The resistance of intrinsic semiconductor decreases with increase of temperature 4 Majority carriers in a n type semiconductor are holes Minority carriers in a p type semiconductor are electrons

The relative density of material of a body is found by weighing it first in air and then in water If the weight in air is 5 00 0 05 Newton and weight in water is 4 00 0 05 Newton Then the relative density along with the maximum permissible percentage error is 1 5 0 11 2 5 0 1 3 5 0 6 4 1 25 5

96 The ratio of maximum deflection of a Cantilever beam due to point load at the free end to that of due to u d l over the entire span giving same total load on the Cantilever is a 3 b 4 7 c 3 8 d 8 3

An unstretched spring of constant 720 N m is attached to pins at points C and I as shown The pin at B is attached to member BDE and can slide along the slot in the fixed plate Determine the force in the spring when a 10 N horizontal force directed to the right is applied at point G 400 mm 200 mm A B C D ww E F ww H 1

sertion Reas STATEMENT 1 An astronaut in an orbiting space station above the Earth experiences weightlessness and STATEMENT 2 of free fall An object moving around the Earth under the influence of Earth s gravitational force is in a state A STATEMENT 1 is True STATEMENT 2 is True STATEMENT 2 is a correct explanation for B STATEMENT 1 is True STATEMENT 2 is True STATEMENT 2 is NOT a correct explanation for STATEMENT 1 C STATEMENT 1 is True STATEMENT 2 is False D STATEMENT 1 is False STATEMENT 2 is True 2008

i If neutrinos were the only contribution to dark matter estimate the average mass of each neutrino assuming that there are equal numbers of neutrinos and photons You may use the present day photon density 22 5 x 10 5 relative to the critical density pel 10 20 kg m 3 Give your answer to the nearest eV 3

Pick out the incorrect statement among the following statements Systematic errors can be minimised by improving experimental techniques O Instrumental erre e due to imperfect design of instrument O Systematic errors are those errors that tend to be in one direction O Least count error belongs to category of random error only

A parachutist jumps from height 100 m He is to reach at ground with zero velocity For this purpose he switches on a parachute propeller after falling freely for certain height Given that after the parachute propeller is switched on total acceleration of the man varies with velocity as a 2v where v is the instantaneous velocity of the man Choose the correct options for this situation use g 10 m s a Man switches on parachute propeller after falling freely for time 4 second b Man switches on parachute propeller after falling freely for time 2 second c Distance covered by the man with parachute propeller switched on is 20 m d Distance covered by the man during free fall is 60 m

20 The potential energy of a particle of mass m is given kx for x 0 and U 0 for x 0 If total by U mechanical energy of the particle is E Then its speed at x 2 a zero 2E is V k b 2E m E c m d E 2m

Anushka is sitting on the edge of a horizontal Merry go around that has a radius of 6m and is rotating steadily Virat is standing still on the ground at a point that is 12m from the centre of the Merry go around Assume their line of sight is horizontal At a particular instant Virat observes Anushka moving directly towards him with a speed of Im s and observes there is no component of velocity perpendicular to the line joining them At the same moment Anushka observes Virat to be moving at a speed m s where n is a non negative integer At the same moment the rate at which Anushka observes the distance between them is decreasing to be m m s where m is a positive integer At the same moment Anushka observes Virat s velocity perpendicular to the line joining them to be p m s where p is non negative integer Choose the CORRECT option s E NARAYANA GROUP A m 1 B n 4 C p 3 D Acceleration of Anushka as observed by Virat is a constant

One mole of an ideal diatomic gas undergoes a process AB as shown The temperature of the gas at which the heat exchange reverses its direction is PA P 7PV B 49 PV 35PV 25 PV

2 A composite A 36 steel bar shown in figure has 2 segments AB and BC Cross sectional area of AB 500 mm and BC is 400 mm The Young s modulus of the steel bar is 210 GPa The bar is subjected to an axial force P 20 kN Determine 1 Displacement of Point C relative to A 8C A 2 Normal strain in each segment 1 m 1 25 m A B C

381 an 26 Two pendulums differ in lengths by 22 cm red ere They oscillate at the same place so that one of them makes 30 oscillations and the other makes 36 oscillations during the same time The lengths in cm of the pendulums are a 72 and 50 b 60 and 38 d 80 and 58 c 50 and 28 ng lar all ge

A car moves at a constant speed on a road as shown in figure The normal force by the road on the car is N and N when it is at the points A and B respectively 2 N N A 3 N N B 4 insufficient

A makeup box which is cuboidal in shape has dimensions 3 042 m 1 234 m x 0 017 m If the mass of the box is 2 123 kg then its density correct to its significant figures A 33 26 kg m B 33 268 kg m C 33 kg m 3 3 D 33 2 kg m 3 3

uestion No 8 The pitch of screw gauge is 1 mm and there are 100 divisions on circular scale While measuring diameter of a wire linear scale reads 1 mm and 39th division c scale coincides with reference line The zero error is 0 05 mm The correct diameter of wire is O 1 39 mm O 1 44 mm O 1 35 mm View in Engli 01 034 mm

Question No 10 In an experiment to measure the height of a bridge by dropping stone into water underneath if the error in measurement of time is 0 1 s at the end of 2 s then ell estimating height of bridge is g 9 8 m s exact O 0 19 m O 1 96 m O 0 98 m 0 12 m