Physics Questions

23 A string is under tension so that its length is increased by times its original length The ratio of 1 n fundamental frequency of longitudinal vibrations and transverse vibrations will be a 1 n c n 1 b n 1 d n 1

27 0 If work done in increasing the size of rectangular soap film with dimensions 8 cm x 3 75 cm to 10 cm x 6 cm is 2 x 10 4 J The surface tension of film in newton per meter is 2 1 x 10 2 1 65 x 10 2 3 3 x 10 2 4 2 x 10 Solution

Soft water is define as CO1 O The water which contains oxygen The water which contains anions of Br 1 S 2 O O O The water which does not contains the salts of Ca 2 Mg 2 The water which contains the salts of Ca 2 Mg 2

In YDSE yellow light of wavelength 6000 produced fringes of width 0 8 mm If the source is replaced by another monochromatic source of wavelength 7500 and separation between slits is same the fringe width becomes 1 mm 0 5 mm 0 6 mm 0 4 mm

1 point 7 Which one of the following is a disadvantage of a potentiometer over a voltmeter Oa it can measure the e m f of a cell Ob it is heavy and not portable O c it can measure accurately very small potential difference of the order of few micro volt Od it can measure the internal resistance of a cell

C C C C3 C3C1 In the circuit shown in the figure each capacitor 12 has a capacity of 3uF The equivalent capacity between A and B is 1 3 4 F 3 3 F 2 6 F 4 SUF ff unfre FAB e ka ar 1 3 4 F 3 3 F 2 6 F 4 5 F B

Please explain clearly 5 A closed vessel in the shape of a truncated cone having semivertex angle 53 have top and bottom radii r and 3r The vessel is full of a liquid of density p The force applied by the walls of the container on the liquid is 1 pg Fr 3r 2 3 r pg

6 Indicate the wrong statement from the following For accurate measurements a potentiometer wire Oa must have a uniform cross section Ob must have a high temperature coefficient of resistance Oc high specific resistance Od homogeneity

1 25 F 3 40 F Separation between the plates of a parallel plate 6 capacitor is d and the area of each plate is A When a slab of material of dielectric constant and thickness t t d is introduced between the plates its capacitance becomes Eo A d t 1 1 2 20 F 4 5 F Eo A d 1 1 1 2 EO A d t 1 COA 4 d t 1 1 25 F 3 40 F Ak qu gain vend f er ft d iz ft and suf unfar at and t X 1 3 2 20 F 4 5 F C A d t 1 2 CA 2 COA d t 1 i to A 4 d 1 1 4

9 The count rate for a radioactive source was found to be 1600 count sec At t 0 and t 8 sec this rate was 100 count sec What was the count rate at t 6 in counts sec 1 4000 3 200 2 300 4 150

If the frequency and intensity of a light source are both 2 doubled Now consider the following statements A The saturation photocurrent remains almost the same B the maximum kinetic energy of the photo electrons is doubled C The maximum kinetic energy of the photoelectrons is increased but not doubled The correct statement s is are 1 B only 3 A and C only 2 A and B only 4 C only

An electrical technician requires a capacitance of 4 F in a circuit across a potential difference of 1000 V A large number of 2 F capacitors are available to him each of which can withstand a potential difference of not more than 200 V The minimum number of capacitors required are

3 3 3 F 4 5 F In fig given C 3 F C SuF C 9 F and 13 C 13uF What is the potential difference between points A and B OF 3 0 V 4 II V 22V 1 13 V 2 9 V A B 3 3 F 4 5 F faff C 3 F C 5 F C 9 F a C 13 F fak Saisy 22V 1 13 V 2 9V 3 0V A B 4 11 V

8 With a certain cell the balance point is obtained at 65 cm from the zero 1 point end of a potentiometer wire With another cell whose e m f is less than that of the first by 0 1 V the balance point is obtained at 60 cm What is the e m f of the first cell Oa 1 0 V Ob 1 2 V Oc 1 3 V Od 1 5 V

A lump of lead with mass 0 5 kg is dropped from height of 20 m onto a hard surface it doesn t rebound but remains there at rest for a long period of time Find change in heat change in work change in internal energy for the lead during this process

vector of the object is A 31 4 12k B 3i 4j 12k C 31 4j 12k A particle goes along a quadrant of a circle of radius 10m from A to B as shown in f the magnitude of displacement and distance along the path AB is 08 0A OA B 8 OB OA A D 19mm

The velocity time graph for a body is shown in the figure Answer the following a calculate the acceleration during the time interval 4s to 8s b find the distance covered in first 8s c time interval when moving with zero acceleration d find the retardation during the journey 4 V m s 12 0 A 4 8 12 t 16 20 t s

The wooden beam is constructed from three boards that are fastened together using nails with s spacing along the beam as s For b 12 in h 5 in and 4 14 in determine the area moment of inertia of the cross section about the neutral axis in b N A 1 in

A block of mass m is placed in a container as shown Height of the block is very close to the height of the container A time dependent force F acts on the system such that resultant downward accel eration of system is given by a at a 0 where t is time Which of the following graphs represents normal reaction of tube on block Take downward direction as positive for for normal reaction N 1 3 Z4 N Z 2 4 Z4 N Z4

Calculate the self gravitational potential energy of matter forming a a thin uniform shell of mass M and radius R and b a uniform sphere of mass M and radius R 1 In a certain region of space gravitational field is given by I K r Taking the reference point to be with V V find the potential as a function of distance r

Anuncharged capacitor of capacitance 10 uF and a coil of inductance 2 mH are placed in series with a battery of emf 60 V The switch is closed Then the maximum energy stored in the capacitor is mJ

A block of mass 6 kg kept on a horizontal smooth surface is act B 16kg ya horizontal force of 48N Find the magnitude and direction of acceleration of the block What is the force applied by the block on the surface and in which direction

In the figure 8 kg and 6 kg are hanging stationary from a rough pulley and are about to move They are stationary due to roughness of the pulley Which of the following statement s is are correct I The force of friction on the rope is 20 N II The force of friction on the rope is 30 N a Only I b Only II c Neither I nor II d None of these O 8 kg 6 kg

For the combination of one prism and 2 lenses shown Find the size in cm of final image when the object whose length is 1 cm is located as shown in figure 45 6 cm n 1 5 45 6 cm 10 cm f 20 cm 5 cm f 10 cm

calculate the force acting on the body if its mass is 10 kg A force of 2 N gives a mass m an acceleration of 5 m s2 and a mass m an acceler acceleration would be produced if both the masses are tied together

Variation of force with time for a body moving along straight line is shown in figure The impulse in N s imparted in the time interval t 0 to t 8 s is 2 F N 2 1 zero 2 4 6 2 8 t s 8 3 8 4 6

33 From the top of a tower T a ball is thrown vertically upwards When the ball reaches h below T its speed is double of what it was at a higher h above T Show that the greatest height attained by the ball above T is 5 h 3 Ans 5 h

In single slit diffraction experiment first minima of rec light A 660 nm coincides with first maxima of other wavelength X What is the value of O 440 nm 470 nm 550 nm 690 nm

5 A circular coil of mean radius of 7 cm and having 4000 turns is rotated at the rate of 1800 revolutions per minute in the earth s magnetic field B 0 5 gauss the maximum emf induced in the coil will be 1 0 29 V 2 5 8 V 3 1 158 V 40 58 V

8 37 A bird is sitting in a wire cage hanging from the spring balance Let the reading of the spring balance be W If the bird flies about inside the cage the reading of the spring balance is W Which of the following is true T Mg 1 W W 2 2 W W 2 3 W W 2 R Me M My 80

F pushes wedge of mass M on a smooth horizontal surface A block of mass m is stationary relative to the wedge then F mF M m D The reaction between M and m is M A Frictional force is equal to mg between M and m B Minimum coefficient of friction between M and m is M m 8 F C Minimum force required to prevent relative sliding between M and m is M m m plane Ignoring the friction at the pulley an

A micro ammeter has a resistance of 10002 and 42 full scale range of 50 A It can be used as a voltmeter or as a higher range ammeter provided a resistance is added to it Pick the correct range and resistance combination 1 50 V range with 10k2 resistance in series 2 5 mA range with 12 resistance in parallel 3 10 mA range with 10 resistance in parallel 4 none of these 50 g ad at sa atcete if y fauna 1000 of factu faits fear and fe 1 10k 2 HHI H 10 xe i HII 5 mA TTH 3 110 mA 4

Find the electric potential of the four charges at the center of the square with q 1 0 x 10 6 C and a 1 m as shown in the diagram 2q a 39 O 5 10 x 10 4 V O 4 30 x 10 4 V O 1 40 x 10 4 V 2 10 x 10 4 V 0 48 m 9 24

direction Mass of block A is 4 kg and that of B is 6 kg a Draw the FBD of each block b Find the contact force between the blocks c find the force given by the block B on the ground BON A 4kg 6kg B

A charged particle having charge q and mass m is projected into a region of uniform electric field of strength with velocity V perpendicular to E Throughout the motion apart from electric force particle also experiences a dissipative force of constant magnitude q E and directed opposite to its velocity If V 6 m s then find its speed when it has turned through an angle of 90 mass m and radius r and the ring is placed on

ALLE A horizontal light ray passes through a prism 7 u 1 5 of angle 4 Further it is incident on a plane mirror M that has been placed vertically By what angle the mirror is rotated so that the ray after reflection becomes horizontal A 1 1 2 2 FM 3 4 4 8

Which of the following statements is are INCORRECT about reference frames In a non inertial reference frame an A isolated particle does not retain a constant velocity B C A reference frame travelling with acceleration relative to an inertial reference frame is a non inertial reference frame In an inertial reference frame velocity vector of an isolated particle changes neither in direction nor in magnitude with time If a block is stationary with respect to an D elevator then reference frame fixed to elevator must be inertial

3 Two copper balls each of mass 6 35g are kept at a separation of 10cm in air If one electron from every 1010 atoms is transferred from one ball to another the force between balls will be atomic weight of copper 63 5amu 1 8 3 10 N 2 4 15 10 N 3 8 3x10 N 4 8 3 102 M

649001 Friction Calculate the magnitude of the deceleration of a snow boarder going up a 4 67 slope assuming the coefficient of friction for waxed wood on wet snow 0 14 40 Please enter a numerical answer below Accepted formats are numbers or e based scientific notation e g 0 23 2 1e6 5 23e 8

If the mass of a hydrogen atom is 1 0078 u and that of a neutron is 1 0087 u then the binding energy of 12C is very nearly equal to 6 lu 931 MeV Ignore binding energy of the hydrogen atom A 920 MeV B 92 MeV C 9 2 MeV D 9200 MeV

5 A car travels first 1 3 of the distance AB at 30 km h next 1 3 of the distance at 40 km h and last 1 3 of the distance at 24 km h its average speed in km h for the whole journey is a 40 b 35 c 30 d 28

45 A lift is coming from 8th floor and is just about t reach 4th floor Taking ground floor as origin an positive direction upwards for all quantities whic one of the following is correct 1 x 0 v 0 a 0 2 x 0 v 0 a 0 3 x 0 v 0 a 0 4 x 0 v 0 a 0

3 0 5 02 10V 4 0 72 10V When a resistance of 2 ohm is connected across 36 the terminals of a cell the current is 0 5A When the resistance is increased to 5 ohm the current is 0 25 A The emf of the cell is 1 1 0 V 2 1 5V 3 2 0 V 4 2 5V 3 0 52 10V 2 2 0 2 02 5V 4 0 7 02 10V 0 25 fara 1 1 0 V 2 1 5V 3 2 0 V 4 2 5V

SolveLancer Test A student uses a copper conductor XY of length 100 cm and moves it in a magnetic flux density of magnitude B 0 05 T with a speed 12 ms 1 as shown in the figure Calculate the emf produced and power dispensed if resistance of circuit is 0 2 0 B X 100 cm

U1 376 Trajectories of two projectiles are shown in figure Let T and T be the time periods and speeds of projection Then I a T T b T T c U U d u u and uz their

22 A wire of length is stretched by a force F to cause an extension x Another wire of same material and same volume but 50 larger in length than the first wire the force required for the same extension will be 3 1 OF 16 3 F 4 2 4 3 615 F 22 3 z t 31 SE 1 3

BEGINNER S BOX particle moves on a circular path of radius r It completes one revolution in 40 s Calculate distance Jacement in 2 min 20 s from point P on the edge of the ground and r 300

of the sur or a lens of roca length 10cm is silvered as shown in figure Radius of curvature of silvered surface is 10cm At a given instant if speed of object is m sec then the speed of image at that instant is a m s What will be the value of a f 10cm 1m sec 14 Object 10 3 cm 1m sec

In transformer power of secondary coil is 1 less than primary coil 2 more than primary coil 3 more in step up and less in step down than primary coil 4 more in step down and less in step up than primary coil

Three uncharged capacitors of capacitane 1 C 2uF and C 3 F are connected as shown in figure to one another and to points A B and D poten tial V 10V V 25V and V 20 V Determine the A B D potential V at point O C 2MF C B A lov FC IMF LOV 3 F C3 11 D 20 V