Physics Questions

The density of a rod gradually changes from one end to the other It is pivoted at one of the end so that it can rotate about a vertical axis through the pivot A horizontal force F is applied on the free end in a direction perpendicular to the rod The quantities that depend on axis of rotation in this situation are angular acceleration B Total kinetic energy of the rod when the rod completes one revolution C Angular momentum when the rod completes one revolution Angular velocity of rod

45 Susceptibility of Mg at 300 K is 1 2 10 45 The temperature at which susceptibility will be 1 8 10 is 1 450 K 2 200 K 3 375 K 4 None of these Mg 300 K 1 2 10 fa 1 8 10 1 450 K 2 200 K 3 375 K 4

The fundamental frequency of a sonometer wire increases by 5 Hz if its tension is in creased by 21 Instead if the length of wire is decreased by 10 than the fundamental frequency becomes B 50 Hz D None of these A 45 45 Hz C 55 55 Hz

5 A circular coil of 0 2 m diameter has 100 turns and carries a current of 0 1 ampere The intensity of magnetic field at the centre of the coil is a 6 28 10 4 N A m c 6 28 10 5 N A m b 62 8 x 10 4 N A m d 62 8 x 10 5 N A m

Where it is used Explain with diagram working of that device State gauss s theorem Use it to find electric field due infinite line of charg What is the effect on electric field when charge density gets double a distance between point and line of charge is half

Why v2 max is root 2g12 For maximum angular displacement 1 2mv 2 2mgl v root 4gl for maximum angular displacement because with this velocity the bob wil not complete full circle but have maximum angular displacement Aug 16 2021 5 47 04 AM Answered A bob of mass m suspended by a string of length I is given a minimum velocity required to complete a full circle in a vertical plane At the highest point it collides elastically with another bob of mass m suspended by a string of length 2 which was initially at rest Both the string are massless and inextensible If the second bob after collision acquires the minimum speed so that bob starts oscillating with maximum possible angular amplitude during its subsequent motion in vertical plane The ratio is Correct answer 02 00

Read the following carefully A Enzymes are denatured at high temperature but in certain exceptional organisms they are effective even at temperature 80 90 C B Enzymes are highly specific C Most enzymes are proteins 6 Enzymes require optimum pH for maximal activity How many is are wrong 1 3 4 B

The coefficient of static friction between the two blocks is 0 363 What is the minimum acceleration of block 1 so that block 2 does not fall A 6 ms C 18 ms 2 2 a B 12 ms D 27 ms

simple harmonic oscillation is 13 of its amplitude Ans E E 8 9 E E 1 9 A particle executes simple harmonic motion with time period 15 seconds and having amplitude 2 2m Find its maximum velocity and acceleration Ans 0 92m sec 0 38m sec

A wheel is rolling on a horizontal plane At a certain instant it has velocity v and acceleration a of c m as shown in the figure Acceleration of B A is vertically upwards B may be vertically downwards C cannot be horizontal Some point on the rim may be horizontal leftwards B

A network of nine conductors connects six points A B C D E and F as shown below The digits denote resistances in 22 Find the equivalent resistance between A and D A 2 B E ww 2 0 B 10 A www DX2 1 www 1 www 0 www F 5 www 2 C O D 11

angle Two stones A and B are thrown simultaneously from a point on horizontal ground The stone A is thrown vertically up with velocity u and the stone B is thrown with speed up at 37 with horizontal After 0 9 S stones are moving perpendicular to each other Then A u 9 ms B u 9 ms C ug 15 ms D ug 9 ms

A lift of mass 1000 kg which is moving with acceleration of 1 m s in upward direction then the tension developed in string which is connected to lift is a 9800 N c 11 000 N b 10 800 N d 10 000 N 2002

The rate of disintegration of a radioactive sample is P at time ty and R at time to The half life of the sample is proportional to Only one correct answer A P C D titty In R R t t In Ry In R In R R tx In R In R

A uniform magnetic field of magnitude 0 20 T exists in space from east to west With what speed should a particle of mass 0 010 g and having a charge 1 0 x 10 5 C be projected from south to north so that it moves with a uniform velocity A 48 m s C 47 m s B 49 m s D 50 m s

91 The radius of the nucleus with nucleon 9 number 2 is 1 5 x 10 15m then the radius of nucleus with nucleon number 54 will be A 3 x 10 15 m C 6 x 10 15 m B 4 5 x 10 15m D 9 5 10 15 m

A car is fitted with a convex side view mirror of focal length 20 cm A second car 2 8 m behind the first car is overtaking the first car at a relative speed of 15 ms The speed of the image of the second car seen in the mirror of the first one is 1 10 c 10 ms a ms b I ms 15 d 15 ms

A compound microscope has an eye piece of focal length 10 cm and an objective of focal length 4 cm Find the magnifica tion if an object is kept at a distance of 5 cm from the objec tive so that the final image is formed at the least distance of distinct vision 25 cm

ve horizontal Which of the following is incorrect 1 As you move from geographic north pole to south pole the magnetic inclination changes 2 As you move from geographic north pole to south pole in a vertical plane the magnetic declination a remains same 3 True angle of dip can be found without placing the compass in the magnetic meridian 21 4 The value of true dip at a place is always greater than the value of apparent din at that placa

A horizontal surface is rough A ring is placed on it with its plane parallel to the surface A charge 9 is uniformly Bot 3 2 distributed on this ring of radius R and mass m At t 0 a uniform magnetic field B QBOR 2mg The coefficient of friction is Find the time at which ring will start rotating about an axis perpendicular to its plane and passing through its centre in seconds 3 A B 1 C L is switched on r

4 Coulomb s Law can be expressed as F A r Use the fitting curve of the data to estimate the value of A Express your estimate with the correct units Hint Do not confuse A with the proportionality constant k of Coulomb s Law BIU Force N 0 006 0 005 0 004 0 003 0 002 0 001 10 15 Force vs Distance 20 25 Distance cm 30 35 40

27 The nucleus 27 14 13 4Si decays to its mirror nucleus 23 Al by positron emission The maximum kinetic energy energy of the positron is 3 48 MeV Assume that the mass difference between the nuclei is due to the Coulomb energy Assume the nuclei to be uniformly charged spheres of charge Ze and radius R Assuming the radius is 1 3 given by A3 find the above dar toest a 1 5 fm b 73 in d 158 fm c 1 62 fm

A If a dielectric is inserted to fill the gap between the plates of a capacitor connected to a battery then electric field inside the capacitor decreases R Magnitude of electric field inside a medium is times the potential gradient in that 1 K medium

The velocities of A and B are marked in the figure 2 183 The velocity of block C is assume that the pulleys are ideal and string inextensible A 5 m s B 2 m s C 3 m s D 4 m s 1 m s AO m s B

07 A square of side a is cut from a square of side 2a as shown in the figure Mass of this square with hole is M Then its moment of inertia about an axis passing through its CM and perpendicular to its plane will be A Ma 6 2a B 2a 2Ma 6

5 A beam of light of wavelength 600 nm from a distant source falls on a single slit 1 00 mm wide and the resulting diffrac tion pattern is observed on a screen 2 m away The distance between the first dark fringes on either side of the central bright fringe is xx104m Find the value of x

if I have two masses of m1 and m2 in vaccu m and the only force between both the mas ses is of the gravitational force how much t ime would it take for both masses to touch each other due to gravitational attraction h ow do we analysie the motion of both objec ts

3 2 mg 4 cube will not reach the point 2 A square conducting loop of side length L carries 23 a current I The magnetic field at the centre of the loop is 1 independent of L 2 proportional L 3 inversely proportional to L 4 linearly proportional to L 4 Na fang 2 PHAN T I m 2 L 3 L 4 L en were it

A current i is uniformly distributed over the 27 cross section of a long hollow cylindrical wire of inner radius R and outer radius R Magnetic field B varies with distance r from the axis of the cylinder as 3 B4 114 2 B4 RARE GRA accurates freen R an art fR ta ha Ba 3 ra hai niem 147 D Y 194 The following statement is false for Helmholtz 28 teater quaferat af coils DA fra feri

An object on a spring vibrates in a simple harmonic motion at a frequency of 4 hertz and an amplitude of 8 cm If the mass of the object is 200 g the spring constant is 40 N m X160 N m 126 N m 109 N m

5 14 A stick of length lies on horizontal table It has a mass Mand is free to move in any way on the table A ball of mass m moving perpendicularly to the stick at a distance d from its centre with speed v collides elastically with it as shown in figure 5 138 What quantities are conserved in the collision What must be the mass of the ball so that it remains at rest immediately after collision M Figure 5 138

An electron initially at rest is accelerated through a potential difference of 200 volt so that it acquires a velocity 8 4 x 106 m s The value of e m of electron will be A 2 76 x 10 2 C kg B 1 76 x 10 C kg C 0 76 x 10 2 C kg D None of these

1 A projectile is fired with a speed u at an angle 0 above the horizontal field The coefficient of restitution between the projectile and field is e Find the position from the starting point when the projectile will land at its second collision 1 2 3 e u sin 20 8 1 e u sin 20 8 1 e u sin cose 8 1 e u sin 20

over a a point 0 V m opper nsions lectric Q 14 Two media I and II are separated by a plane surface having speeds of light 2 108 m s and 2 4 x108 m s respectively What is the critical angle for a ray going from I medium to II 1 sin 3 sin 2 5 12 2 sin 4 sin 5 6 2

15 The wedge shown in the figure can slide without friction on a horizontal tabletop The mass of the wedge is M and its angle of elevation is a 30 A body of mass m slides down without friction along the wedge the path of the body makes an angle of 60 with the ground Find the ratio of the masses m M a M 6

Question 1 Answer the following questions very briefly 1 Forces always occur in pairs 2 Mass in motion 3 According to It seems reasonable that acceleration should be inversely proportional to the mass of the body 4 No force is needed to keep an object moving with constant velocity was

n this question the y component of vel ocity of rain is in downwards direction o in answer the y component will be wi n negative sign one of these 10 A man starts running along a straight road with uniform velocity observes that the rain is falling vertically downward If he doubles his speed he finds that the rain is coming at an angle to the vertical The velocity of rain with respect to the ground is

Q 13 In a vernier callipers ten smallest divisions of the vernier scale are equal to nine smallest division on the main scale If the smallest division on the main scale is half millimeter then the Least Count of Vernier Callipers is 1 0 5 mm 2 0 1 mm 3 0 05 mm 4 0 005 mm

Three resistances are in parallel The currents in the first two resistors are 1A and 2 A The voltage across the third resistor is 100 volts The total power dissipated is 500 watts Determine total resistance of the circuit 10 ohm 20 ohm 30 ohm 40 ohm

17 A body initially at rest and sliding along a frictio track from a height h as shown in the figure completes a vertical circle of diameter AB D height h is equal to 3 A D

In a compound microscope the magnified virtual image is formed at a distance of 25 cm from the eye piece The focal length of its objective lens is 1 cm If the magnification is 100 and the tube length of the microscope is 20 cm then the focal length of the eye piece lens in cm is

Find the angular position 0 where the elec tric field due to an electric dipole is perpen dicular to the dipole moment P 0 E A tan 3 C tan 5 B tan 2 D tan 7

A thin rod is hinged at one end O and it is in an unstable equilibrium position It falls under gravity due to a slight disturbance It makes angles 60 90 and 180 with vertical in positions 2 3 and 4 respectively If 2 03 04 are angular velocities at these positions then A 4 203 B 04 20 C 4 1 5 2 D 004 2002 O 60 90

8 A charge Q is uniformly distributed over a large plastic plate The electric field at a point P close to the centre of the plate is 10 V m If the plastic plate is replaced by a copper plate of the same geometrical dimensions and carrying the same charge Q the electric field at the point P will become 1 Zero 2 5 V m 3 10 V m 4 20 V m

eus ent in triton mbers P v rm into 2He not allowed because of ins a b Fusion processes are impossible at ordinary temperatures and pressures nuclei are positively charged and nuclear forces are short range strongest forces 0 9 Samples of two radioactive nuclides A and B are taken and are the disintegration constants of A and B respectively In which of the following cases the two samples can simultaneously have the same decay rate at any time a Initial rate of decay of A is twice the initial rate of decay of B and A Ag b Initial rate of decay of A is twice the initial rate of decay of B and AA B c Initial rate of decay of B is twice the initial rate of decay of A and Ag d Initial rate of decay of B is same as the rate of decay of A att 2h and Ag A Ans b d The two samples of the two radioactive nuclides A and B can simultaneously have the decay rate at any time if initial rate of decay of A is twice the initial rate of decay of Also when initial rate of decay of B is same as rate of decay of A att 2har dioactive samples A and B with

Spring pendulum is on the rotating table Initial angular velocity of the table is w and time period of pendulum is To Now the angular velocity of table becomes 2w then new time period will 1 2T 2 T 2 Remains same 12

49 The difference in the coulomb energy between the mirror nuclei Cr and Mn is 6 MeV Assuming th the nuclei have a spherically symmetric charge distribution and that is approximately 1 0 MeV fim Fi the radius of the Mn nucleus 49 25 and hom of mding Rin

Q 2 Two pendulums each of length 1 are initially situated as shown in figure The first pendulum is released and strikes the second Assume that the collision is completely inelastic and neglect the mass of the string and any frictional effects How high does the centre of mass rise after the collision The 7 d 1 Ma

0 4 2t a b 4 What is the average velocity of a projectile between the instants it crosses half the maximum height if it is projected with a speed u at an angle 0 with the horizontal 1 u sin 0 2 u cos 0 3 u tan0 4 H

2 6 For the arrangement shown in figure the tension in the string to prevent it from sliding down is m 1 kg 1 6 N 19 O ANT 37 0 8 2 6 4 N AT